Effect of inbreeding on pseudo-self-compatibility in red clover (Trifolium pratense L.)

Summary The effect of inbreeding on pseudo-self-compatibility (PSC) was investigated in I₀, I₁, and I₂ clones of red clover, Trifolium pratense L., at 40°C. PSC was found to decrease with inbreeding. Significant differences were found among I₀ clones, among I₁ clones, and among I₂ clones for PSC. Significant differences in PSC within generations were found in two of eight I₁ clones and one of five I₂ clones.A new method of inbred line maintenance is proposed which combines the desirable features of vegetative and seed maintenance of inbred lines. Superior I₁ clones with different but homozygous S genotypes and PSC values of 8 to 10% would be vegetatively increased. Clones would be isolated under high temperature field conditions and selfed seed (PSC) would produce the I₂. Selfed seed from two different I₁ clonal lines would then be mixed and sown to produce single-cross seed. Singlecross seed obtained from different clonal sources would be mixed and sown for the production of double-cross hybrid red clover.Contribution from the Kentucky Agricultural Experiment Station. This paper (72-3-125) is published with approval of the Director, Kentucky Agricultural Experiment Station, Lexington.     

Effect of generation of inbreeding, cutting treatment and year on agronomic traits in berseem populations

The selfing effect in berseem clover (Trifolium alexandrinum L.) was analysed by comparing generation means for nine agronomic traits (dry matter yield, plant height, leaf-stem ratio, harvest index, seed yield and its components). Parents, S₁, S₂, S₃, and S₄ generations of six populations of different geographical origin (3 from Egypt and 3 from southern Italy) were investigated to estimate the relative changes with increasing homozygosity and to prove the effectiveness of selfing in a breeding program. The experiment was carried out at Foggia (Italy) under field conditions for two years (1995 and 1996) adopting two cutting treatments: at fifth internode elongation (A) and flowering (B). The mean values decreased with the advancement in selfing generations in both years and cutting treatments for the most of the traits. Treatment B yielded more biomass and seed yield than treatment A in both years. Cutting treatments did not affect the adaptability of the selfed progenies of populations with different geographical origin, in fact, the Italian populations were more productive for dry matter under both cutting treatments (856.6 g m^-2 on average), whereas Egyptian populations proved superior for seed yield particularly under treatment B (62.5 g m^-2 on average). Inbreeding depression was greater for forage dry matter and seed yield (−62and −79% on average, respectively), whereas the plant height and 1000-seed weight were the least susceptible traits (−26 and −19% on average, respectively). Estimates of the parameters of the stability analysis showed that not all populations responded to inbreeding level and environment variations to the same degree. Differences were evident under treatment A, only. Development of self-fertile, relatively vigorous inbred lines of berseem clover with different degrees of homozygosity appears possible. Genotypes tolerant to selfing from Egyptian and Italian groups have been obtained by inbreeding and selection for self-fertility; they could be utilised as basis for producing new breeding activities. This revised version was published online in July 2006 with corrections to the Cover Date.     

Interaction among sporophytic S loci in self-incompatible garden chrysanthemums

Summary Certain parent-progeny crosses were studied to determine whether several S loci acted independently or epistatically to produce incompatibility in garden chrysanthemums, Chrysanthemum morifolium Ramat. The ratios of compatible: incompatible crosses with the original parent, as the pollen parent, were nearly 1:3, 1:1, and 1:1 for the I₁, backcross (BC), and BCF₂ generations, respectively. In particular, crosses between each progeny and the original parent showed that the number of compatible crosses was much higher than expected if each S locus acted independently. Therefore, interaction must have existed among pollen S alleles from different S loci. This information was used to demonstrate a method by which garden chrysanthemums could be inbred by sib mating in successive generations.Scientific Journal Series Paper Number 13,001 of the Minnesota Agricultural Experiment Station.     

Inheritance of downy mildew resistance at cotyledon and adult-plant stages in ‘Couve Algarvia’ (Brassica oleracea var. tronchuda)

Parasitic nematodes damage white clover (Trifolium repens) roots, negatively impacting forage yield and persistence. No single gene resistance to nematodes has been identified in white clover. Trifolium semipilosum (2n = 2x = 16) genotypes exhibiting either complete resistance or susceptibility to infection by the clover root-knot nematode (CRKN), Meloidogyne trifoliophila, were identified. F₁ progeny (n = 92) of a pair-cross between ‘TsR’, a plant heterozygous for the resistance phenotype and ‘TsS’, a plant homozygous for the susceptible phenotype, were challenged with infective CRKN juveniles and evaluated subsequently for root galling. Segregation analysis indicated the resistance phenotype may be conferred by a single dominant allele at a locus (designated TRKR, Trifolium Root-knot Resistance) subject to segregation distortion. TsR, TsS, and bulked resistant and bulked susceptible F₁ progeny (n = 12/bulk) were screened using T. repens microsatellite (SSR) markers. Three SSRs revealed polymorphism in TsR and the resistant bulk, of which prs090 and prs247 map to loci on T. repens linkage group D2. Progeny were genotyped with these three SSRs and 23 additional SSRs from T. repens groups D1 and D2. Linkage analysis in both TsR and TsS demonstrated macro-synteny between T. repens group D homoeologues and the T. semipilosum linkage group (designated D_Ts) containing the TRKR locus. Significant segregation distortion was detected in TsR, and recombination in the central region of the T. semipilosum linkage group was suppressed relative to T. repens in both parents. These data demonstrate the opportunities and challenges for comparative mapping in Trifolium and characterisation of loci conferring resistance to plant-parasitic nematodes.     

Effect of inbreeding on horticultural performance of lines developed from an open-pollinated pickling cucumber population

Summary The effect of self-pollination of cucumber (Cucumis sativus L.) for 6 generations in lines developed from the North Carolina Medium Base Pickle population was determined by regression of trait expression for each generation on Wright's coefficient of inbreeding. Two yield traits (total and marketable), earliness and 3 fruit quality traits (shape, color and seedcell size) were evaluated in 2 environments (spring and summer, 1983). The regression did not result in significant negative slopes, indicating that inbreeding depression was not important in the population for the traits studied. Midparent heterosis was found for most traits in many hybrids obtained from crossing S₆ lines with the gynoecious inbred line, Gy 14A.     

Variation and covariation for quantitative resistance to head blight (Fusarium culmorum) in two testcross series of S2 lines in winter rye

The amount of genetic variation among inbred lines and testcrosses, and covariation between both genetic materials, are of crucial importance for selection efficiency in hybrid breeding. To estimate these quantitative genetic parameters for resistance of winter rye (Secale cereale) to head blight caused by Fusarium culmorum, 88 three-way cross hybrids, produced by crossing each of 44 S₂ Carsten inbred lines with two unrelated Petkus single-cross testers, were evaluated along with the parental lines over 2 years. Resistance traits were head-blight rating and grain weight per spike relative to the non-inoculated control. Significant genotypic variation occurred among lines and in both testcross series. S₂ lines displayed considerably more variation than testcross series. Genotype × environment interaction was more marked among the inbred lines, while estimates of heritability were similar for both genetic materials. Testcrosses showed heterosis for head-blight resistance. No relationship existed between S₂ lines and the two testcross series for any resistance trait. This might be caused by an association between inbreeding and Fusarium-head-blight susceptibility and different inbreeding depression among the S₂ population. The phenotypic correlations between the testcross series were moderate for both traits (r = 0.58, P < 0.01). In conclusion, Fusarium-head-blight resistance has to be selected at the respective heterozygosity levels.     

Breeding maize lines for complete and partial resistance to maize streak virus (MSV)

Summary S₁ to S₅ inbred lines, derived from a maize population bred for its overall resistance to three tropical viruses, were screened for resistance to maize streak virus (MSV) by artificial plant infection using viruliferous leafhoppers. Symptoms were rated and intra-line frequency distributions studied for all pedigree inbred lines. Mortality due to MSV was very low among these inbreds. Symptoms appeared later, developed slower and were less severe than in the susceptible control hybrid. Results of a study of 500 S₁ and 93 S₂ lines suggested that resistance is under genetic control via a system involving loci with major genes (with dominance for resistance) controlling high to complete resistance, associated with a genetic system involving loci with minor genes controlling partial resistance. Lines expressing complete resistance to MSV were developed from 5 cycles of inbreeding and selection. The relevance of such complete and partial resistance is discussed.Abbreviations MRPS Mean Rating for Plants exhibiting Symptoms     

Plant growth habit,root architecture traits and tolerance to low soil phosphorus in an Andean bean population

The optimal plant growth habit and architecture of common bean (Phaseolus vulgaris L.) is dependent on environmental conditions. The objectives of this research were to determine if plant growth habit impacts a plant’s ability to grow in low P conditions, as measured by P uptake, seed yield, and P use efficiency and to determine if aboveground plant growth habit and root growth are associated at variable P soil levels. The study was carried out with recombinant inbred lines developed from an Andean intra-gene pool cross between a low P tolerant parent with an indeterminate growth habit (G19833) and a low P susceptible parent with a determinate growth habit (AND696). The population was grown for 2 years in low and sufficient P conditions in a field site in Darien, Colombia. In the first season, indeterminate lines had 15% more seed yield than the determinate lines in the low P treatment, whereas there was no difference by growth habit in the high P treatment. In the second season, seed yield and tolerance to low P was not influenced by growth habit. Root architectural characteristics such as root length density (RLD) and root surface area were 25% and 34% greater respectively in the indeterminate lines under P-sufficiency, whereas under low P, root architecture traits were not significantly different by growth habit. Root plasticity was higher in determinate lines, although RLD and root surface area did not play a significant role in tolerance to low P. Overall, the data were consistent with shoot growth habit as playing a complex and important role in adaptation to P-deficiency.     

Genetic and statistical models for estimating genetic parameters of maize seedling resistance to Fusarium graminearum Schwabe root rot

Root lodging is an important problem in corn fields. Fungi recovered from roots include seedling blight and stalk rot pathogens. The objective of this work was to study the inheritance of maize seedling resistance to pathogens causing maize lodging. The Fusarium graminearum strain, 241 Fr1, was isolated from maize lodged plants and identified as the most pathogenic isolate for root rotting. Nine inbred lines of maize and their diallel F₁ crosses plus control genotypes were studied. Seedlings were inoculated at the stage of four-leaves. Disease severity was measured as percentage of the root rotted area. Highly significant differences between inoculated and non-inoculated genotypes were found. Four genetic models and two statistical approaches—the mixed model for the best linear unbiased prediction (BLUP) and the general linear model (GLM)—were used for the analysis. Favorable heterosis of resistance of hybrids over inbreds was the most important effect detected. The general combining ability (GCA) effects were significant for all genetic models and statistical methods studied, and a good agreement existed among the GCA estimates by the different methods. The type of gene action, either additive or dominance, showed a large variation among the parental inbreds and hybrids. Selection of additive effects based exclusively on inbred lines is not sufficient to confer resistance to hybrids, additional selection should be practiced on hybrids to look for favorable dominance effects. This revised version was published online in July 2006 with corrections to the Cover Date.     

剪根与水分胁迫对小麦单根和细胞导水率及TaPIP基因表达的影响

剪去小麦部分根系能瞬间打破其水分平衡,研究根系导水特性对剪根的响应有助于解释静水压对作物根系吸水的调节机制。通过对苗期小麦(Triticum aestivum)剪根与水分胁迫处理,用压力探针技术测定单根和细胞两种尺度上的根导水特性变化,以及根中TaPIP1;2和TaPIP2;5的转录调节变化。结果显示,剪根处理或水分胁迫处理使叶片蒸腾速率和气孔导度均显著低于对照,而单根导水率和细胞导水率均与对照无显著差异。剪根处理的叶片蒸腾速率、气孔导度、叶水势、单根导水率和细胞导水率均显著高于水分胁迫处理,而剪根且水分胁迫处理的各参数均显著低于其他处理。各处理的单根导水率与细胞导水率显著正相关。各处理根中TaPIP1;2和TaPIP2;5相对mRNA含量的变化规律与单根和细胞导水率的变化规律相似。剪根处理显著上调了TaPIP1;2和TaPIP2;5转录,水分胁迫处理显著下调了其转录,但TaPIP1;2和TaPIP2;5在剪根且水分胁迫处理中的转录水平最低。这些结果表明,小麦的根导水特性在单根尺度和细胞尺度上具有一致性;剪根短期内能够增加小麦幼苗的水分敏感性。推测TaPIP1;2和TaPIP2;5参与了静水压对小麦根导水特性的调节过程。     

Genetic factors influencing the regeneration ability of rye (Secale cereale L.). II. Immature embryos

Summary Immature embryos of seven rye inbred lines were cultured on modified MS medium containing 3 mg/dm^–3 2,4-D. According to thein vitro response lines were divided into four groups: (1) those producing non-embryogenic callus (NEC) from above 30% of the embryos and having a high rate of non-responding (NR) embryos, (2) those producing non-embryogenic callus (NEC) from the majority of embryos, (3) those producing NEC by the majority of embryos with a high percentage of calli regenerating roots, (4) those producing embryogenic callus (EC) and regenerating plants by above 50% of the embryos. The inheritance of these response types was analysed in F₁, F₂, and F₃ generations of crosses of some lines. The results obtained indicate that EC production and both plant and root regeneration are determined by recessive genes whereas the reduced ability for NEC production most probably by dominant genes. The lack of response is controlled by at least two interacting genes.     

Hybrid performance and heterosis in strawberry (Fragaria × ananassa Duchesne), regarding acidity,soluble solids and dry matter content in fruits

A top‐cross‐mating design among 29 S₄ inbred lines and tester (cultivar ‘Dukat’) was carried out to study their breeding value in terms of general combining ability (GCA). The objectives of this study were to evaluate the acidity, soluble solids and dry matter contents in fruits of progeny F₁ in comparison with S₄ inbred lines as well as the cultivars (S₀); identify strawberry genotypes with high value of GCA for use in cultivar development; and determine mid‐parent heterosis regarding S₄ inbred lines and cultivated strawberry. The 2‐year observations showed statistically significant differences between tested genotypes in terms of the studied traits. The highest breeding value based on GCA was estimated for Chandler 123‐5 for soluble solids and dry matter content, and Kent 7‐6 for acidity. Estimated mid‐parent heterosis had positive and negative values. The highest heterosis in terms of extract and dry matter content (26.71% and 17.50%, respectively) occurred in the offspring Chandler 123‐5 × ‘Dukat’, but as regards acidity in hybrid Chandler 123‐22 with cv. ‘Dukat’. The study of genetic divergence by dendrograms may help to identify parents suitable for obtaining hybrids with higher heterosis effects.     

Differences in nitrogen fixation among field-grown red clover strains at different levels of 15N fertilization

Summary Genetic variation in fixed nitrogen (N) yield of red clover (Trifolium pratense L.) strains and cultivars was investigated using the ¹⁵N isotope dilution method under three regimes of N fertilization: 0.5, 30, and 60 N (kg N ha^–1 per cut). The yield of fixed N per cut (the mean of eight cuts over 2 production years) varied among the strains (progenies of crosses between inbred parents) from 148 to 443 mg per plant at 0.5 N, from 76 to 324 mg at 30 N, and from 69 to 300 mg at 60 N. There were significant and consistent strain differences in the percentage of clover N derived from the atmosphere (% N_dfa). However, %N_dfa was positively correlated with dry mass yield. Consequently, ranking of the strains according to fixed N yield reflected that of dry mass yield. There were only minor strain × N fertilizer interactions, suggesting that selection for enhanced N fixation can be carried out at a single rate of fertilizer N. For a selected pair of strains, the difference in yield of fixed N was confirmed in an Italian ryegrass-red clover mixture, both without and with the addition of N fertilizer (50 kg N ha^–1 per cut). Results with 7-week-old seedling plants in a growth chamber, although obtained in the presence of mineral N and with the isotope dilution method, did not adequately predict field performance. It is concluded that selection for dry matter or total N yield is likely to result in an enhanced yield of fixed N at any level of mineral N availability.Abbreviations % N_dfa percentage of clover nitrogen derived from the atmosphere by symbiotic nitrogen fixation - S₂-F₁-n progeny of pair cross between inbred parents obtained after two generations of selfing     

Identification of qRL7, a major quantitative trait locus associated with rice root length in hydroponic conditions

Root system development is an important target for improving yield in rice. Active roots that can take up nutrients more efficiently are essential for improving grain yield. In this study, we performed quantitative trait locus (QTL) analyses using 215 recombinant inbred lines derived from a cross between Xieqingzao B (XB), a maintainer line with short roots and R9308, a restorer line with long roots. Only a QTLs associated with root length were mapped on chromosomes 7. The QTL, named qRL7, was located between markers RM3859 and RM214 on chromosome 7 and explained 18.14–18.36% of the total phenotypic variance evaluated across two years. Fine mapping of qRL7 using eight BC₃F₃ recombinant lines mapped the QTL to between markers InDel11 and InDel17, which delimit a 657.35 kb interval in the reference cultivar Nipponbare. To determine the genotype classes for the target QTL in these BC₃F₃ recombinants, the root lengths of their BC₃F₄ progeny were investigated, and the result showed that qRL7 plays a crucial role in root length. The results of this study will increase our understanding of the genetic factors controlling root architecture, which will help rice breeders to breed varieties with deep, strong and vigorous root systems.     

Screening and selection of eggplant and wild related species for resistance to <Emphasis Type="Italic">Leveillula taurica</Emphasis>

Screening for resistance to powdery mildew of Solanum melongena and wild related species was made in the field under natural infection conditions. A total of 172 accessions originating from several geographical parts of the world were tested. Single plant selection for resistance was carried out and open-pollination was used. Most S. melongena accessions were susceptible or highly susceptible to the disease. By S₀ to S₃ selection, an increase in the overall powdery mildew resistance level of S. melongena population was obtained and four S. melongena lines possessing a high level of resistance were obtained. Among the wild Solanum species, S. laciniatum and S. nigrum showed to be non-host plants of L. taurica. S. quinquangolare showed no symptoms of powdery mildew, S. linnaeanum, S. aculeatissimum, S. aviculare, S. pseudocapsicum were highly resistant, S. spinosissimum was resistant, S. gilo, S. capsicoides were susceptible or highly susceptible, and plants of S. sisymbriifolium showed a widely variable disease reaction. Four S. melongena resistant lines were obtained: PAVEG 10187 S₃, PAVEG 10196 S₃, P.I. 230279 S₃ and P.I. 419198 S₃. These S. melongena lines together with the resistant wild species could be used for genetic studies, classical breeding programs and biotechnological applications.     

Investigations on the inheritance of color and carotenoid content in phloem and xylem of carrot roots (Daucus carota L.)

Summary Investigations on the inheritance of root color in carrot (Daucus carota L.) were carried out by crossing uniformly colored roots to various tinge type roots, i.e. roots of which the xylem differs in color from the phloem.A single major gene (Y) was found to be responsible for the observed differences in progenies of orange x tinge orange-white (orange referring to phloem color, white to xylem color) crosses. Plants carrying the dominant Y-allele had either white or tinge orange-white roots, whereas plants with orange roots were of the genotype yy. Similarly one major gene (Y ₂) determined the segregation found in progenies of orange x yellow crosses. In the latter crosses, plants having the dominant Y ₂-allele had either yellow or tinge orange-yellow roots while the recessive would be orange. Variation in phloem color, i.e. differences between white and tinge orange-white or between yellow and tinge orange-yellow, was apparently caused by minor genes, modifiers, gene interactions, or by genes that are not involved in carotenogenesis in a direct way.When both the Y- and Y ₂-genes were present, the roots were always white. Usually white roots gave a digenic segregation pattern in the F₂ when crossed to orange, but there was some evidence that a third gene (Y ₁) was segregating in some crosses. Tinge orange-white x yellow crosses gave approximately the same results as orange x white crosses, confirming that the same Y- and Y ₂-genes were segregating.In crosses between orange lines and a light yellow line (RY) certain F₁ 's appeared to have a light orange xylem and a fairly dark orange phloem, which seems to be some evidence for the existence of recessive yellow. Although almost nothing is known yet about the genetics of RY it is assumed that it still carries a dominant inhibitor gene which may be leaky in heterozygous condition. The value of such a line as an aid in the selection of superior orange lines is discussed.Alpha- and beta-carotene were found to be the major pigments in orange carrot tissue; phytofluene, zetacarotene, gamma-carotene and xanthophylls were shown to be present in smaller amounts. Besides xanthophylls and a small amount of beta-carotene dark yellow carrot tissue appeared to contain an appreciable amount of an unidentified pigment (pigment I). Light yellow and white phloem or xylem tissue were low in total carotenoids.Research supported by the College of Agricultural and Life Sciences and by a grant from the Campbell Soup Company, Camden, New Jersey, USA. The investigation is a portion of a thesis submitted in 1978 as partial fulfillment of the requirements of the PhD degree.     

Estimates of heritability for,and relationships between,root and shoot characters of white clover. I. Replicated clonal material

Summary A total of 749 genotypes from a number of white clover (trifolium repens L.) cultivars and populations, many collected from dryland areas, were cloned and grown in field titles. Several morphological characters, including leaf size, number and diameter of large nodal roots (taproots), and proportion of root weight that was classified as taproot were measured. There was large variation between lines and genotypes for all characters measured, and differences between genotypes within lines are also reported. Broad sense heritability estimates were higher (>0.5) for leaflet width, petiole length and stolon diameter, than for all root character heritability estimates which were between 0.2 and 0.4.     

Molecular markers linked to the <Emphasis Type="Italic">fin</Emphasis> gene controlling determinate growth habit in common bean

The S-genotypes of 16 apricot (Prunus armeniaca L.) cultivars native to China were determined by the S-allele PCR approach and the results were confirmed by cross-pollination tests among these cultivars. Primer combination EM-PC2consFD + EM-PC3consR, based on the conserved regions C2 and C3 of Rosaceous S-RNase genes, was the most useful primer combination for identifying Chinese apricot S-alleles. Twelve S-RNase alleles were identified using this primer combination, and they were defined as follows: S ₉ was 657 bp, S ₁₀ was 266 bp, S ₁₁ was 464 bp, S ₁₂ was 360 bp, S ₁₃ was 401 bp, S ₁₄ was 492 bp, S ₁₅ was 469 bp, S ₁₆ was 481 bp, S ₁₇ was 487 bp, S ₁₈ was 1337 bp, S ₁₉ was 546 bp and S ₂₀ was 1934 bp. S ₁₁–S ₂₀ were new S-RNase genes deposited in GenBank under accession numbers DQ868316, DQ870628-DQ870634, EF133689 and EF160078, respectively. Our findings contribute to a more efficient breeding program of Chinese apricot and further studies on the S-RNase genes.     

Localization of QTL for basal root thickness in <Emphasis Type="Italic">japonica</Emphasis> rice and effect of marker-assisted selection for a major QTL

Root traits are key components of plant adaptation to drought environment. By using a 120 recombined inbred lines (RILs) rice population derived from a cross between IRAT109, a japonica upland rice cultivar and Yuefu, a japonica lowland rice cultivar, a complete genetic linkage map with 201 molecular markers covering 1,833.8 cM was constructed and quantitative trait loci (QTLs) associated with basal root thickness (BRT) were identified. A major QTL, conferring thicker BRT, located on chromosome 4, designated brt4, explained phenotypic variance of 20.6%, was selected as target QTL to study the effects of marker-assisted selection (MAS) using two early segregating populations derived from crosses between IRAT109 and two lowland rice cultivars. The results showed that the flanking markers of brt4 were genetically stable in populations with different genetic backgrounds. In the two populations under upland conditions, the difference between the means of BRT of plants carrying positive and negative favorable alleles at brt4 flanking markers loci was significant. Phenotypic effects of BRT QTL brt4 were 5.05–8.16%. When selected plants for two generations were planted at Beijing and Hainan locations under upland conditions, MAS effects for BRT QTL brt4 were 4.56–18.56% and 15.46–26.52% respectively. The means of BRT for the homozygous plants were greater than that of heterozygous plants. This major QTL might be useful for rice drought tolerance breeding. L. Liu and P. Mu are contributed equally to this work.     

Magnitude of inbreeding depression and genetic variation analysis of agro‐morphological traits in orchardgrass

Inbreeding depression is the reduction in the fitness of inbred offspring relative to progeny from unrelated parents. In orchardgrass (Dactylis glomerata L.), limited efforts have been made to evaluate the effects of deliberate selfing on agro‐morphological traits and to estimate the genetic variation of traits. Twenty‐five genotypes of orchardgrass, along with 25 S₁ (full‐sibs) and 25 families of half‐sibs, were created in 2012 and used to assess the consequences of the first generation of inbreeding and outcrossing for offspring fitness and to estimate heritabilities, genetic parameters and correlations of agro‐morphological traits during the period of 2013–2014 in the field. Different levels of inbreeding depression were observed for the traits, with higher values for plant height, days to inflorescence emergence and dry matter yield. The degree of inbreeding or outbreeding effects varied among the studied genotypes. This facilitates the development of inbred lines for further studies. The results showed that some of the studied genotypes were self‐fertile, thereby indicating the possibility of developing inbred lines from these genotypes. Heritabilities ranged from 0.10 for the number of stems per plant to 0.64 for spread among the studied populations. Spread had high heritability as well as high correlation with forage yield, thereby indicating that this trait could be used to improve forage yield indirectly.