Genetic variability and heterotic groups of Brazilian popcorn populations

The development of successful advanced lines and cultivars in maize is dependent on parental selection and assignment to defined heterotic groups. So, the objectives of this study were to evaluate genetic variability and identify heterotic groups among Brazilian popcorn varieties. Thus, diallel crosses of advanced generations of the popcorn hybrids, IAC 112 and Zélia, and of three open-pollinated popcorn varieties, RS 20, Branco, and SAM were performed. Ten hybrid combinations, the five parents, and five check treatments were arranged in a block design with four replicates in two tropical-zone locations (CWb climate). Both additive and non-additive effects were important for grain yield, plant height, ear height, and husk cover. For popping expansion, only the additive effects were important. Hybrid combinations between the local variety (Branco) and F₂ populations (IAC 112 and Zelia) resulted in the third and fourth highest values for popping expansion. The best grain yields were obtained with hybrid combinations involving SAM. Cultivars Zélia, IAC 112, and RS 20 increased popping expansion, whereas cultivar Branco increased grain yield of hybrid combinations. The following conclusions may be drawn: Brazilian popcorn populations have reduced heterosis and genetic variability to popping expansion in relation commercial cultivars; there is genetic variability among Brazilian popcorn populations that allows the exploitation of additive and non-additive effects for grain yield; it is possible to increase grain yield by using local varieties; but it would be difficult to obtain commercial hybrids from local varieties because they have poor performance for popping expansion.     

Genetic variance components and genetic effects among eleven diverse upland cotton lines and their F2 hybrids

Selecting high yielding upland cotton, Gossypium hirsutum L. lines with improved fiber quality is a primary breeding goal. A diverse set of ten cultivars and one breeding line were crossed in a half diallel. Parents and F₂ hybrids were grown in three environments at Mississippi State, MS. Ten agronomic and fiber traits were analyzed by a mixed linear model approach based on the additive-dominance genetic model. Variance component, genetic effects and genetic correlations were calculated. ‘Acala Ultima’ was a desirable general combiner for fiber length, uniformity, strength, micronaire, lint percentage, and boll weight. ‘FiberMax 966’ was a desirable general combiner for fiber length, uniformity, strength, and all agronomic traits. ‘Tamcot Pyramid’ and M240 were poor general combiners for both fiber and agronomic traits. ‘Coker 315’ was a good general combiner for fiber length, uniformity, micronaire, boll weight, boll number, and yield. Heterozygous dominance effects were associated with several crosses, which suggest their use as hybrids.     

Evaluation of genetic variances, heritabilities, and correlations for yield and fiber traits among cotton F2 hybrid populations

Summary F₂ hybrid cultivars continue to occupy a small portion of the cotton (Gossypium hirsutum L.) production are in the United States, but occupy a larger proportion of the production area in some other countries. Sixty-four F₂ hybrids resulting from crosses of four commercial cultivars and 16 pest-resistant germplasm lines were evaluated for five fiber and four yield traits in four environments at Mississippi State, MS. An additive-dominance genetic model was employed for these traits. The minimum norm quadratic unbiased estimation (MINQUE) method was used with a mixed model approach for estimating genetic variance and covariance components and for predicting genetic correlations. This study investigated genetic variances, heritabilities, and genetic and phenotypic correlations between agronomic and fiber traits among these 64 F₂ hybrid populations and discussed the usefulness of these populations for use as hybrids or for selections for pure lines.Dominance variance accounted for the major proportion of the phenotypic variances for lint yield, lint percentage, and boll size indicating that hybrids should have an advantage for these traits compared to pure lines. A low proportion of additive variance for fiber traits and the significant additive x environment variance components indicated a lack of substantial useful additive genetic variability for fiber traits. This suggests that selections for pure lines within these F₂ populations would have limited success in improving fiber traits. Genetic and phenotypic correlation coefficients were of comparable magnitude for most pairs of characters. Fiber strength showed a positive additive genetic correlation with boll weight. Dominance genetic correlations of fiber strength with elongation and 2.5% span length were also significant and positive; however, the additive genetic correlation of length and strength was zero.Contribution of the USDA-ARS in cooperation with the Mississippi Agric. and Forestry Exp. Stn.     

Smut reaction of pearl millet hybrids affected by fertility restoration and genetic resistance of parental lines

Summary Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids based on the A₁ cytoplasmic-nuclear male-sterile (CMS) lines are more susceptible to smut (Tolyposporium penicillariae Bref.) than open-pollinated varieties. Seventy eight pairs of hybrids, made onto male-sterile (A) lines and their counterpart maintainer (B) lines, were evaluated to examine the effects of male sterility and genetic resistance of parental lines on the smut severity of hybrids. The A-line hybrids had higher smut severity and lower selfed seedset than the counterpart B-line hybrids, indicating that it is the CMS-mediated male sterility rather than the A₁ cytoplasm per se that caused greater smut severity of A-line hybrids. However, with the use of resistant parental lines even male-sterile hybrids of A-lines, in several cases, were as resistant as some of the highly resistant male-fertile hybrids of B-lines. It would be possible to produce smut resistant hybrids (< 10% severity) on A-lines, albeit in low frequency, even if only one parent of a hybrid were resistant. However, the probability of producing such hybrids would be higher when both parents were resistant to smut. Thus, improvement in smut resistance of parental lines and fertility restoration ability of pollinators would provide the most effective genetic approach to smut disease management in hybrids.Submitted as JA No 1737 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).     

Genetic effects on biomass yield in interspecific hybrids between Brassica napus and B. rapa

This study was conducted to estimate the genetic effects on biomass yield in the interspecific hybrids between Brassica napus and B. rapa, and to evaluate the relationship between parental genetic diversity and its effect on biomass yield of interspecific hybrids. Six cultivars and lines of oilseed B. napus and 20 cultivars of oilseed B. rapa from different regions of the world were chosen to produce interspecific hybrids using NC design II. Obvious genetic differences between B. rapa and B. napus were detected by RFLP. In addition, Chinese B. rapa and European B. rapa were shown genetically differences. Plant biomass yield from these interspecific hybrids were measured at the end of flowering period. Significant differences were detected among general combining ability (GCA) effects over two years and specific combining ability (SCA) effects differences were detected in 2000. The ratios of mean squares, (σ² _GCA(f) + σ² _GCA(m)) / (σ² _GCA(f) + σ² _GCA(m) + σ² _SCA), were 89% and 88% in 1999 and 2000, respectively. This indicates that both additive effects and non-additive effects contributed to the biomass yield of interspecific hybrids and the former played more important role. Some European B. rapa had significant negative GCA effects while many of Chinese B. rapa had significant positive GCA effects, indicating that Chinese B. rapa may be a valuable source for transferring favorable genes of biomass yield to B. napus. Significant positive correlation between parental genetic distance and biomass yield of interspecific hybrids implies that larger genetic distance results in higher biomass yield for the interspecific hybrids. A way to utilize interspecific heterosis for seed yield was discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

The production of inbred lines of brussels sprouts with dominant S-alleles

Summary The best sources of Brussels sprout inbred lines with both good agronomic characters and high self-incompatibility are likely to be cultivars of reasonably good agronomic type which have not been too intensively selected. Comparison of three cultivars of different agronomic quality showed that the cultivars of poor and moderate quality had about 55% of plants with a dominant S-allele, but the most highly selected cultivar had only 25% of such plants. A programme of S-allele screening is suggested which incorporates the minimum number of tests required to determine whether or not a particular plant has a dominant S-allele. A survey of S-alleles present in commercial F₁ hybrids showed that the frequency of dominant S-alleles was only 19% in hybrids released prior to the end of 1971, but was 50% in hybrids released since 1971.     

Creation of new maize germplasm using alien introgression from <Emphasis Type="Italic">Zea mays</Emphasis> ssp. <Emphasis Type="Italic">mexicana</Emphasis>

Zea mays ssp. mexicana, an annual wild relative of maize, has many desirable characteristics for maize improvement. To transfer alien genetic germplasm into maize background, F₁ hybrids were generated by using Z. mays ssp. mexicana as the female parent and cultivated maize inbred line Ye515 as the male parent. Alien introgression lines, with a large range of genetic diversity, were produced by backcross and successive self-pollinations. A number of alien introgression lines with the predominant traits of cultivated maize were selected. Genomic in situ hybridization (GISH) proved that small chromosome segments of Z. mays ssp. mexicana had been integrated into the maize genome. Some outstanding alien introgression lines were evaluated in performance trials which showed 54.6% hybrids had grain yield greater than that of hybrid check Yedan12 which possessed 50% Ye515 parentage, and 17.1, 9.9% hybrids had grain yield competitive or greater than those of Nongda108 and Zheng958, which were elite commercial hybrids in China, respectively. The results indicated that some of the introgression lines had excellent agronomic traits and combining ability for maize cultivar, and demonstrated that Z. mays ssp. mexicana was a valuable source for maize breeding, and could be used to broaden and enrich the maize germplasm.     

Cytology and digoxin production in hybrids between Digitalis lanata and D. grandiflora

Summary Digitalis lanata is the only commercial source of the cardiac glycoside digoxin. It is an outbreeder and displays considerable variation. An attempt to increase uniformity was made by making D. lanata × D. grandiflora diploid hybrids and from these produce allotetraploid hybrids using colchicine treatment. Such tetraploid plants would be homozygous. Tetraploid hybrids were shown to contain digoxin but at lower levels than in D. lanata. Progeny of selfed tetraploid hybrids were significantly more uniform than D. lanata grown from commercial seed, but were considerably less vigorous.     

Heritability estimates of spaced-plant traits in three perennial ryegrass (Lolium perenne L.) cultivars

Summary Seed yield in perennial ryegrass is low and unpredictable. Spaced-plant traits suitable for indirect selection for total seed yield in drilled plots would be very useful. The objectives of this investigation were to evaluate genetic variation for seed yield components and other traits among clones from three perennial ryegrass cultivars differing in seed yield and their open-pollinated progenies. Per cultivar, a random set of 50 genotypes was cloned and on each genotype seed was generated by open pollination. Clonal ramets of the parents were observed for 17 traits in 1986 at two locations. In 1987 and 1988, parents and progenies were observed as single plants in a randomized complete block design with two replications. There was little cultivar-environment interaction for most traits. The parents differed significantly for almost all traits. Half-sib (HS) families differed for only three to five traits. Broad-sense heritabilities (h² _b), based on variance components of the parents, were moderate to high; earliness had the highest h_b ². Narrow-sense heritabilities (h² _n), based on variance components among HS-families, were low to moderate and mostly not significant; for most traits h² _n estimates varied between years and cultivars. Flag leaf width and date of first anthesis showed the highest h² _n. Narrow-sense heritability estimates from parent-offspring regressions (h² _nPO) ranged from non-significant to high, depending on year and cultivar; they were generally higher than the corresponding h² _n estimates. Generally, h² _nPO was highest for earliness, flag leaf width, ear length and the number of spikelets per ear. Breeding methods that capitalize on additive genetic variance, such as mass selection, should result in improvement for these traits.     

Colchicine mutagenesis is associated with substantial heritable variation in cotton

Summary Seedlings of the cotton cultivar Sicot 1 were treated with either 1%, 2% or 5% colchicine in lanolin which was topically applied to the apical meristem four days after emergence. Of 293 1%-treated seedlings 64 survived to produce fertile C₁ shoots which gave rise to 84 C₂ single boll families. C₂ and C₃ generations were examined in field experiments for morphological variants and for a number of quantitative characters (yield components and fibre quality). No morphological mutants were seen but considerable heritable variation for metrical characters of economic importance was detected. Of 18 extreme C₂ families consisting of 54 C₃ progenies, 19 were shown in a replicated spaced-plant trial to be significantly different to the Sicot 1 parental material for at least one (usually more) characters. The 222 C₃ progenies of the 66 non-extreme C₂ families were tested in an unreplicated plot experiment and at least 14 were suspected of exhibiting variation in metrical characters. Although no light has been shed on the mechanism responsible for the production of variants by this method, it is argued that the colchicine technique results in higher levels of genetic variation than found in commercial cultivars; variation which can be readily exploited by cotton breeders.     

Improvement of large-seeded common bean cultivars under sustainable cropping systems in Spain

Approaches are needed to broaden the genetic base and improve earliness and yield potential of large-seeded beans under sustainable cropping systems. The objective of this research was to develop adapted dwarf bean populations having a commercial seed quality and yield suitable for the production in the South of Europe. The original base populations were produced from crosses between genotypes within each Mesoamerica, Nueva Granada and Peru races, and between Peru and Nueva Granada, and Mesoamerica and Nueva Granada races. Visual mass selection for plant performance was practised in the F₂ and F₃ generations. In the F₄ and F₅, single plants were harvested under two cropping systems (sole cropping and intercropping with maize). From F₄, selection was based on precocity, combined with seed yield and seed commercial type. The F_4:7 selected lines from each original population were compared with their parents and five checks at four environments and two cropping systems. Differences among environments, populations, parents and checks were observed for all traits. Under intercropping with maize, there was a 50% reduction in seed yield. Yield of parents and checks belonging to Andean South American races, intraracial (Nueva Granada × Nueva Granada) and interracial (Nueva Granada × Peru) populations, was higher than that of those of Middle American origin. Intraracial crosses within large-seeded Andean South American (Peru race) and Middle American gene pools (Mesoamerica race) did not produce lines yielding more than the highest yielding parent. Only two large-seeded lines selected from crosses between small- and large-seeded gene pools out-yielded the best parent and check cultivar.     

Genetic impacts of fiber sugar content on fiber characters in Sea Island cotton, Gossypium barbadense L.

A genetic model with additive effect, dominant effect, additive × additive effect, and their interaction with environment effect (GE) was employed to analyze the 2-year data of F₁ and F₂ hybrids from 5 × 4 diallel cross, whose parents were Sea Island cotton with different fruit branch types. Unconditional and conditional genetic variances were analyzed to demonstrate genetic impacts of fiber sugar content on fiber characters. Results of unconditional genetic variances showed that dominance × environment interaction effect and additive × additive epistatic effects mainly controlled the genetic variation of fiber sugar content, and environment influenced the inheritance of fiber sugar content. Fiber uniformity, fiber elongation, and fiber micronaire were mainly controlled by dominance × environment effects. Fiber strength was mainly controlled by the interaction of additive × additive epistatic effects and the environment. Analysis of correlation coefficients indicated that the varieties or hybrids with high-fiber sugar content had short fiber, low-fiber uniformity, strength, and fineness, which indicated the close co-variation between fiber quality traits and fiber sugar content. Relatively better fiber quality traits could be obtained effectively through selecting parents with low-fiber sugar. Fiber sugar content of different parents had different genetic effect on fiber quality traits.     

Genetic improvement of cell-wall digestibility in forage maize (Zea mays L.). I. Performance of inbred lines and related hybrids

Summary The current study deals with genetic improvement of the nutritive value of forage maize. In separate field trials, maize inbred lines without the brown midrib trait and derived hybrids were evaluated for stalk quality as well as some other agronomic traits. The aim was to relate the performance of lines and hybrids. Quality traits studied were the contents of ash and cell walls expressed as percentage of dry matter and the digestibilities of organic matter and cell walls (stalk-dv% and stalk-dcw%, respectively). The performance of hybrids was established in a trial at two locations with three replicates per location and the performance of lines at one location in an unreplicated trial.The range for stalk-dcw% was about 10 percentage units between hybrids and 15 percentage units between inbred lines. Stalk-dcw% had of all quality traits of hybrids the highest broad-sense heritability (h ²=0.74), and determined about 80% of the variation in stalk-dv%. The only stalk quality trait where a significant correlation was found between the mean hybrid performance and the corresponding midparent value was stalk-dcw% (r=0.70, P<0.01).In conclusion, stalk-dcw% proved to be the only stalk quality trait worth evaluating at the inbred line level in a breeding programme aimed at producing commercial hybrid varieties of forage maize.     

Genetic diversity in bread wheat, as revealed by coefficient of parentage and molecular markers, and its relationship to hybrid performance

Variable results have been obtained in different crop species using geneticsimilarity (GS) estimates based on molecular markers and coefficient ofparentage (COP) to predict heterosis.This study was designed: i) to assess the level of GS among 40 breadwheat (Triticum aestivum L.) cultivars selected in Central and SouthEurope; ii) to compare GS with COP; iii) to correlate the estimates ofparental diversity with the heterotic effects detected on 149 F₁hybrids obtained by crossing the 40 cultivars according to three matingdesigns.The parental cultivars and the F₁ hybrids were grown in severallocations at normal seed density. Significant heterotic effects were detectedfor grain yield and other traits including quality attributes. The parentalcultivars were assayed for DNA polymorphisms using two classes ofmarkers: 338 RFLP and 200 AFLP^® bands were scored. GS estimates werecomputed considering each molecular marker set separately (GS_RFLP,GS_AFLP) and together (GS_TOT). Ample differentiation amongthe parental cultivars was detected with the two marker sets. Although theaverage GS_TOT (0.43) was higher than COP (0.10), the twomeasurements were significantly correlated (r = 0.36, p < 0.01).Correlations between the different estimates of genetic diversity andF₁ performance or mid parent heterosis for grain yield and otherrelated traits were in general low although statistically significant.A more detailed analysis was conducted on 28 F₁ hybridsproduced in a half diallel cross of eight parental cultivars characterized byhigh heterotic effects for grain yield. The GS estimates based on RFLP,AFLP^® markers and also on RAPD were partitioned into general andspecific components. Correlations with general and specific combiningability effects for the measured traits were in several cases statisticallysignificant but too low to be predictive and therefore exploitable in practicalbreeding.     

The effect of T-DNA on the agronomic performance of transgenic flax plants

Summary Registration and commercial release of crop cultivars improved using recombinant DNA technologies will require extensive field testing of the transgenic lines. In addition to testing the efficacy of the transferred gene(s), regulatory bodies and farmers need data from large scale agronomic studies to provide assurance that the foreign DNA does not adversely affect normal agronomic productivity or quality of the crop. Here, five transgenic sulfonylurea resistant flax (Linum usitatissimum) lines were included in a multiple location cultivar registration trial, evaluated and compared with four standard commercial cultivars and 24 other (conventionally produced) breeding lines. The transgenic lines did not appear to be affected by T-DNA for any quality or agronomic parameter tested, including yield.     

Genetic association of cotton yield with its component traits in derived primitive accessions crossed by elite upland cultivars using the conditional ADAA genetic model

Boll number, lint percentage, and boll weight are three component traits for lint yield of upland cotton, Gossypium hirsutum L. Selecting high yielding lines or hybrids depends on the ability to dissect the genetic relationship of lint yield with these component traits. In this study, 14 day-neutral lines with desirable fiber quality derived from primitive accessions were top crossed with five commercial cultivars. The F₂ populations and parents were grown in one location in 1998 and two locations in 1999 at Mississippi State, MS. The F₃ populations and parents were grown in two locations in 2000. Lint yield and three component traits were measured and analyzed by the ADAA genetic model with the mixed model based conditional approach. Results showed that boll number or boll number with lint percentage or boll weight contributed to the majority of the phenotypic variance and variance components for lint yield. Boll number was more important than the other two component traits in terms of various genetic effects. The results also showed that the combination of boll number and boll weight greatly increased the contribution to lint yield even though boll weight itself had no significant contribution to lint yield compared to boll number alone. The genetic contribution effects were also predicted due to single component traits or their combinations for parents and crosses. The results revealed that the balanced selection of boll weight and boll number should be considered to obtain high yielding hybrids or pure lines. Contribution of the USDA-ARS in cooperation with the Mississippi Agric. and Forestry Exp. Stn. Mention of trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by USDA, ARS and does not imply its approval to the exclusion of other products or vendors that may also be suitable.     

Breeding widely adapted, popular maize hybrids

Summary World trend is to more maize hectarage grown to fewer, more widely-adapted hbrids. My purpose is to document research events leading to the most popular corn hybrids, Pioneer Brand 3780 and 3732. I provide background on maize adaptedness, on the seed maize business, on commercial maize hybrid development process, and on cultural practice change. I provide historical information on the cultivars: Leaming corn, Reid Yellow Dent, and Minn. 13 were widely-adapted open-pollinated varieties. Shift from open-pollinated to hybrid maize caused a shift in emphasis from local to wider adaptation. The first widely-adapted hybrids were Iowa 939 and U.S. 13. DEKALB 404A was the first popular and most popular double-cross hybrid. Pioneer 349 was the second-most popular double-cross hybrid. The first popular single cross hybrids were DEKALB 805 in medium and DEKALB XL45 in early U.S. Corn Belt in the early-1960's. Cultural practices (higher planting density, narrower rows, more nitrogen, better pesticides, and larger equipment allowing more timely operations) changed greatly in the 1960's and 1970's; allowing fewer, more widely-adapted genotypes to prevail. First hybrid 3780, then 3732 became the most popular hybrid; each exceeded one billion (1 × 10⁹) dollars sales. They were the result of wide-area testing, of utilizing higher plant density stress for selecting inbred lines and for screening hybrids, and of modern information management.     

Use of molecular markers to accelerate the breeding of common bean lines resistant to rust and anthracnose

The main goal of this work was to introduce resistance genes for rust, caused by Uromyces appendiculatus, and anthracnose, caused by Colletotrichum lindemuthianum, in an adapted common bean cultivar through marker-assisted backcrossing. DNA fingerprinting was used to select plants genetically closer to the recurrent parent which were also resistant to rust and to race 89 of C. lindemuthianum. DNA samples extracted from the resistant parent (cv. Ouro Negro), the recurrent parent (cv. Rudá), and from BC₁, BC₂ and BC₃ resistant plants were amplified by the RAPD technique. The relative genetic distances in relation to the recurrent parent varied between 9 and 59% for BC₁, 7 and 33% for BC₂, and 0 and 7% for BC₃ resistant plants. After only three backcrosses, five lines resistant to rust and anthracnose with, approximately, 0% genetic distance in relation to the recurrent parent were obtained. These lines underwent field yield tests in two consecutive growing seasons and three of them presented a good yield performance, surpassing in that sense their parents and most of the reference cultivars tested.     

Heterosis and heritability in crosses among Asian and Ethiopian parents of hot pepper genotypes

Hot pepper is the most important worldwide grown and consumed spice and vegetable crop. Though hybrid breeding has been proposed for genetic improvement in the crop, but there is lack of information on heterosis in crosses among crop genotypes in Ethiopia. Twelve genotypes (nine Asian and three Ethiopian parents) of hot pepper were crossed in 2003 cropping season in a half-diallel fashion to fit Griffing’s fixed effect model analysis. An open field experiment was conducted in 2004/2005 to investigate heterosis for fourteen traits in 66 F₁ hybrids grown together with their 12 selfed parents. Highly significant genotypic differences were observed for all the traits except for leaf area. Variance component due to specific combining ability (dominance) were larger than that due to general combining ability (additive) for each of the studied traits with few exceptions. Broad sense heritability (H _b²) for fruit traits were more than 60% and with wide gap from narrow sense heritability (h _n²) for most of the important traits like number of fruit per plant (H _b² = 88.3% and h _n² = 46.0%), days to maturity (H _b² = 87.2% and h _n² = 23.1%) and dry fruit yield per plant (H _b² = 72.6% and h _n² = 14.6%). Maximum heterosis over mid-parent and better-parent, and economic superiority of hybrid over standard check were recorded, respectively for dry fruit yield per plant (163.8, 161.8 and 92.1%), number of fruits per plant (104.4, 79.6 and 136.4%) and days to maturity (−29.8, −31.5 and −23.6%). These observations suggested a possibility of utilizing dominance genetic potentiality available in diverse genotypes of the crop by heterosis breeding for improving hot pepper to the extent of better economic return compared to the current commercial cultivar under production in the country. Low narrow sense versus very high broad sense heritability for days to maturity and dry fruit yield per plant could be a sign for achievability of earliness and high fruit yield using heterosis in hot pepper. The maximum heterobeltiosis were recorded either from F₁s obtained from Ethiopian and Asian crosses or from within Asian crosses, suggesting the possibility of maximizing heterosis by considering genetically diverse parental genotypes. The manifestation of highest heterosis in hybrids from among Asian lines indicated existence of genetic diversity among Asian genotypes and the potentiality for improvement of hot pepper using genotypes from different regions of the world along with elite inbred lines from local cultivars.     

Fertility improvement in tetraploid pearl millet

Summary Autotetraploid (2n=4x=28) pearl millet inbred lines, Tift 23BE and Tift 239DB, have been developed for use in crosses with other polyploid Pennisetum species. Each line set less than 1% and 3% selfed and open-pollinated seed, respectively. Seed germination was usually less than 17%. First generation (F₁) hybrids between the two inbreds set up to 61% seed while up to 40% of the seed from hybrids germinated.Seed weight per inflorescence for two planting dates averaged 0.32 g and 3.06 g for the two inbreds and the second generation F₂ progeny, respectively. One hundred seed weight was also significantly higher (0.78 g vs 0.48 g) in the F₂ progeny, probably due better endosperm development. Chromosome behavior and pollen stainability were similar in the inbred parents and hybrids. However, the hybrids shed more pollen than the inbred parents.Heterosis was evident in the F₁ hybrids and F₂ progeny which showed significant increases in plant height, leaf length, leaf width, and inflorescence length in addition to fertility improvement.