Pollen and coenocytic microspore germination in male-fertile and malesterilemsl soybean

Summary Light and fluorescence microscopy were used to study coenocytic microspore germination from male-sterile (ms1 ms1) soybean plants. Anther squashes from male-sterile plants revealed that a low frequency of natural coenocytic microspore germination occurred in male-sterile anthers of four independent lines; [ms1-North carolina (T260H),ms1-Urbana (T266H),ms1-Tonica (T267H), andms1-Ames (T268H)]. Abnormalities such as giant tubes, branched tubes, tubes with swollen areas, and multiple tubes were observed from coenocytic microspores from all four lines. The Urbana line, however, demonstrated a higher percentage of coenocytic microspore germination than did the other three lines. Flowers of the Urbana line from both malefertile and male-sterile plants, as well as gynoecia pollinated with coenocytic microspores from sterile plants, were used for in vivo studies. Pollen-tube growth appeared normal in male-fertile plants. In contrast, coenocytic microspore tubes rarely were observed in gynoecia from male-sterile plants or in gynoecia from malefertile plants that had been artificially cross-pollinated withms1 ms1 plants. Few tubes from coenocytic microspores were observed in the vicinity of the micropylar region. A low frequency of seed set was achieved in the greenhouse on Urbana male-sterile plants grown in the absence of male-fertile plants. Thus, we believe either that some gametes from coenocytic microspores are able to participate in fertilization at low frequency or that apomixis occurs inms1 ms1 plants.Joint contribution: Agricultural Research Service, U.S. Department of Agriculture, and Journal Paper No. J-12310 of the Iowa Agriculture and Home Economics Experiment Station, Ames IA, 50011 USA. Project 2471.     

小麦抗赤霉病基因库研究 Ⅵ.轮选品系与原始亲本的综合分析与比较

用２６个来自基因库的轮选品系或抗源材料和１９个原始亲本，在赤霉病单花接种条件下，对抗性和１６个农艺性状进行综合分析与比较。平均而言，从接种后１６－１７到２６－２７天，病小穗数和病小穗率的扩增值，轮选品系比原始亲本分别少１．３２个和７．１１％。     

Induction of an alloplasmic male-sterile Brassica oleracea by substituting cytoplasm from ‘Early Scarlet Globe’ radish (Raphanus sativus)

Summary Alloplasmic male-sterile Brassica oleracea L. was synthesized in a backcrossing program through amphidiploid Raphanobrassica by using Early Scarlet Globe radish (Raphanus sativus L.) as the donor of cytoplasm and B. oleracea broccoli and cabbage as recurrent pollen parents. Persistence of radish chromosomes and high female sterility were encountered in the first four backcrosses. Following use of colchiploid 4x broccoli as pollen parent, a BC₅ plant was obtained that had 2n=3x+1=28 chromosomes, improved seed set, and no radish traits. The BC₆ with recurrent 2x broccoli contained male-sterile plants with 2n=18 or 19 chromosomes, increased seed set, and broccoli morphology. Subsequent generations segregated for male-sterile and restored male-fertile plants, some with variable development of stamens and pollen. Leaf color of the alloplasmic plants, especially seedlings, was lighter green than normal.     

Discovery of new male-sterile cytoplasm sources and development of a new cytoplasmic-nuclear male-sterile line NJCMS3A in soybean

Most of the cytoplasmic-nuclear male-sterile (CMS) lines of soybean were developed only from a limited cytoplasm sources and performed not as good as required in hybrid seed production, therefore, to explore new male-sterile cytoplasm sources should be one of the effective ways to improve the pollination and hybridization for a better pod-set in utilization of heterosis of soybeans. In the present study, total 80 crosses between 70 cultivated and annual wild soybean accessions and three maintainers (N2899, N21249, and N23998) of NJCMS1A were made for detecting potential new sources with male-sterile cytoplasm. The results showed that in addition to the crosses with N8855.1 (the cytoplasm donor parent of NJCMS1A) and its derived line NG99-893 as cytoplasm parent, there appeared three crosses, including N21566 × N21249 and N23168 × N21249, with male-sterile plants in their progenies. According to the male fertility performance of backcrosses and reciprocal crosses with the tester N21249, the landrace N21566 and annual wild soybean accession N23168 were further confirmed to have male-sterile cytoplasm. Accordingly, it was understood that the source with male-sterile cytoplasm in soybean gene pool might be not occasional. The results also showed that the genetic system of male sterility of the newly found cytoplasm source N21566 was different from the old cytoplasm source N8855.1, while N23168 was to be further studied. Based on the above results, the derived male-sterile plants from [(N21566 × N21249) F₁ × N21249] BC₁F₁ were back-crossed with the recurrent parent N21249 for five successive times, and a new CMS line and its maintainer line, designated as NJCMS3A and NJCMS3B, respectively, were obtained. NJCMS3A had normal female fertility and stable male sterility. Its microspore abortion was mainly at middle uninucleate stage, earlier than that of NJCMS1A and NJCMS2A. The male fertility of F₁s between NJCMS3A and 20 pollen parents showed that 7 accessions could restore its male fertility and other 13 could maintain its male sterility. The male sterility of NJCMS3A and its restoration were controlled by one pair of gametophyte male-sterile gene according to male fertility segregation of crosses between NJCMS3A and three restorers. The nuclear gene(s) of male sterility in NJCMS3A appeared different from the previously reported CMS lines, NJCMS1A and NJCMS2A. The development of NJCMS3A demonstrated the feasibility to discover new CMS system through choosing maintainers with suitable nuclear background.     

Selection for protein content in soybean from single F<Subscript>2</Subscript> seed by near infrared reflectance spectroscopy

Soybean seed averages about 40% protein and is a dominant source of protein in animals and human foods. Increasing protein in soybeans is a goal in soybean breeding programs. Initial selection for protein among progeny from breeding populations is often based on non-destructive Near Infrared Reflectance (NIR) spectroscopy analysis of a 5 g or more seed sample in the F₃ or later generations. NIR spectroscopy analysis for protein on single F₂ seed would allow selection at the earliest possible time and improve selection efficiency for protein content; however this practice has not been evaluated. The objective of this study was to test effectiveness of NIR spectroscopy analysis of single F₂ seeds to select for increased protein content from two populations developed from high and average protein content parents. F₂ seeds from a single F₁ plant of each population showed a normal distribution with transgressive segregation for protein concentration. In both populations, F₃ seeds produced from plants from single F₂ seeds with either low or high protein content were analyzed for protein by NIR spectroscopy. Protein means and ranges of F₃ seed selected from high protein F₂ seeds were higher in protein than F₃ seed from low protein F₂ seeds which produced low means and ranges in protein content. This shows that analysis of single F₂ seed for protein content using NIR spectroscopy was effective in selecting for increased protein in the F₃ generation. Analysis of single F₂ seeds from breeding populations will improve breeding efficiency for protein in soybean breeding programs.     

Genetics of Seed Yield and its Components in Common Bean (Phaseolus vulgaris L.) of Middle-American Origin

Genetic variance, heritability, and expected response from selection arc useful in devising alternative methods and criteria of: selection. The objectives of this study were to estimate these for seed yield and its components from 200 F₂: populations involving 80 cultivars and lines of mostly small-seeded dry bush bean (Phaseolus vulgaris L.) of habits growth I, II, and III of Middle-American origin. All cultivars and lines were crossed in eight sets of ten parents each in a Design II mating system. The F₂ populations, without parents, were evaluated in the field in a replicates-in-sets design at two locations in Colombia in 1983. Estimates of additive genetic variance were significant for yield, pods/m², seeds/pod, and seed weight. Interaction with environments was also significant. Values for nonadditive genetic variance were not significant for either yield or yield components. The estimates of narrow sense heritability, based on the F₂ population mean and unbiased by genotype x environment interaction, were 0.21 ± 0.13 for yield. 20 ± 0.13 for pods/m², 0.57 ± 0.13 for seeds/pod, and 0.74 ± 0.15 for seed weight. The expected direct response from selection of the top 20 % of F₂ populations for yield per se would result in a 4.30 % increase in yield with a correlated response of 0.21 % in seed weight. In contrast, the expected gain from direct selection for seed weight would result in a 11.76 % increase in seed weight with a, correlated gain of 0.28 % for yield. Direct selection for pods/m² would decrease yield, seeds/pod and seed weight, while direct selection for seeds/pod would reduce pods/m² and seed weight but increase seed yield by 0.37 %. Data on yield from replicated trials in the early segregating generations could be utilized for identification and selection of promising crosses and families or lines with crosses for dry bean yield improvement.     

Effects of recurrent selection for resistance to scab (Gibberella zeae) in wheat

Summary Scab caused by Gibberella zeae Petch., in common wheat, is one of the most severe diseases in China. A source population C0, bred for scab resistance, was developed through three cycles of multiple-parent crossing and intercrossing by means of the dominant male-sterile gene Ta1 (Ms2), according to Wu's scheme. Phenotypic recurrent selection methods for increasing the resistance to scab-infection of spikelets and seeds with the male-sterile plants were carried out simultaneously in Nanjing and Shanghai and at Jianyang, Fujian Province, for three cycles. The generations from C0 to C3 and two check cultivars were evaluated, using a randomized block design, under conditions of an artificially induced epidemic of scab during 1988–1990. The results indicate that there were significant differences in the resistance to scab between these generations. On average, the percentages of diseased spikelets and seeds of the male-fertile plants were reduced by 9% and 10%, respectively. The frequency of resistant plants was distinctly enhanced by recurrent selection. Analysis of variance showed that no significant differences existed between cycles of recurrent selection in agronomic characters such as plant height, spikes per plant, spike length, numbers of spikelets and seeds per spike, weight of seeds per spike and 100-kernel weight, days to heading and to maturity. Except for plant height, most of these traits tended to be slightly improved with improvement of resistance in the gene pool. The variance for resistance in the generations was decreased under selection. Recurrent selection for scab resistance using the dominant male-sterile gene Ta1 (Ms2) was both an effective and feasible breeding method for producing this character in wheat.     

Alternative strategies of recurrent selection for seed yield of soybean

Summary Recurrent selection programs can be manipulated by varying either the extensiveness of testing used to identify superior lines or the number of intermating generations conducted among the superior lines between cycles of selection. The research was conducted to compare the performance of soybean (Glycine max (L.) Merr.) lines derived from populations developed by recurrent selection for seed yield using a factorial arrangement that combined one or two stages of replicated yield testing to identify superior lines with one or three generations of intermating among the selected lines. The base population AP6, which was used for this evaluation of alternative strategies of recurrent selection, was derived from 40 high-yielding strains of Maturity Groups 0 to IV. For this study, the 40 original parents of AP6 and the lines used as the parents for the most advanced cycle of selections for each of the strategies were evaluated in four Iowa environments. The number of cycles of selection completed for the strategies under evaluation varied from two to five. Strategies with two stages of replicated yield testing to select superior lines resulted in a larger number of high-yielding lines than when only one stage of testing was conducted. A larger number of high-yielding lines was obtained from strategies with one generation of intermating than when three generations were used. With the procedures used for the one-stage and two-stage tests in this study, the results indicated that an appropriate strategy for recurrent selection of seed yield in soybean would involve two stages of replicated yield testing to identify superior lines and one generation of intermating among the selected lines to form a new population.Journal Paper no. J-12025 of the Iowa Agriculture and Home Economics Experiment Station, Projekt 2475, Ames, IA.     

Correlated response to recurrent selection for groat-oil content in oats

Summary One hundred random oat (Avena sativa L.) lines from a base (C₀) and each of three populations (C₁, C₂, and C₃) improved for groat (caryopsis) oil content by phenotypic recurrent selection were evaluated for correlated changes in several unselected agronomic traits. In addition, the parents of the base population and four check varieties were evaluated for the same traits. Phenotypic recurrent selection for high groat-oil content resulted in no significant correlated response in mean expression of any trait. Mean grain yield, biomass, groat yield, and harvest index of the improved populations were equal or superior to the mean of the parents and, with the exception of harvest index, equivalent to the mean of the check varieties. Mean test weight and seed weight of all populations were lower than for parents or check varieties. Selection for high groat-oil content caused a decline in genotypic variance for test weight and groat fraction, but reductions in genotypic variance for heading date and plant height may have resulted from culling for good agronomic type. Broad-sense heritability remained moderate to high for all traits except groat fraction. Phenotypic and genotypic correlation coefficients revealed negative, though mostly nonsignificant, relationships between groat-oil content and several traits, which may reflect a purported bioenergetic limitation to increasing groat-oil content in oats. Oil yield, however, was positively correlated with grain and groat yield, groat fraction, biomass, and harvest index. Results suggest that development of high-oil oat cultivars with current levels of production traits via phenotypic recurrent selection is possible.Journal Paper no. J-13038 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011. Project 2447.     

Modified full-sib selection and best linear unbiased prediction of progeny performance in a European F2 maize population

Four cycles of modified recurrent full‐sib (FS) selection were conducted in an intermated F₂ population of European flint maize. The objectives of our study were to monitor trends across selection cycles in the estimates of population mean, inbreeding coefficients and variance components, and to investigate the usefulness of best linear unbiased prediction (BLUP) of progeny performance under the recurrent FS selection scheme applied. We used a selection rate of 25% for a selection index, based on grain yield and dry matter content. A pseudo‐factorial mating scheme was used for recombination. In this scheme, the selected FS families were divided into an upper‐ranking group of parents mated to the lower‐ranking group. Variance components were estimated with restricted maximum likelihood (REML). Average grain yield increased 1.2 t/ha per cycle, average grain moisture decreased 20.1 g/kg per cycle, and the selection index relative to the F₂ check entries decreased 0.3% per cycle. For a more precise calculation of selection response, the four cycles should be tested together in multi‐environmental trials. We observed a significant decrease in additive variance in the selection index, suggesting smaller future selection response. Predictions of FS family performance in Cn + 1 based on mean performance of parental FS families in Cn were of equal precision as those based on the mean additive genetic BLUP of their parents, and corresponding correlations were of moderate size for grain moisture and selection index.     

Effects of divergent selection for seed protein content in high‐protein vs. food‐grade populations of early maturity soybean

Due to the growing need for vegetable protein in Central European agriculture, there is interest in producing food‐grade soybeans, which are higher in seed protein and sucrose content and have a larger seed size than conventional soybeans. As protein content of conventional soybean is often below 400 g/kg, either high‐protein or food‐grade donors were crossed with adapted genotypes in order to increase their protein level. After divergent selection for protein content, lines were evaluated for seed quality characters across three environments in Austria. The objectives of this research were to determine the roles of genetic background and the selection for protein content on food‐grade soybean traits. While seed protein content of adapted parents was between 395 and 420 g/kg, its range was from 410 to 490 g/kg for the high‐protein and from 390 to 450 g/kg for the food‐grade lines, respectively. However, food‐grade populations were superior in seed size and sucrose content and revealed different correlation patterns between quality traits as compared to high‐protein populations, which demonstrates their usefulness for developing soybeans with improved quality.     

Autotetraploidy in caraway (Carum carvi L.) for the increase of the aetheric oil content of the seed

Summary An autotetraploid population of caraway (Carum carvi L.) was produced by treating the growing points of young plants with a 0.2% colchicine solution. Selection on morphology, pollen size and pollen shape, followed by a selection on seed size proved to be an effective way to identify the mixoploid C₀ plants. Three percent of the treated plants produced a tetraploid progeny. Moderate selection in the C₁ and the C₂ population resulted in an improvement of the average seed-set to the amount of 50% of the diploid control, with a range of 21–78%. The 1000-kernel weight of the tetraploid material was 7 g, compared to 3 g in the diploid control. The oil content of the autotetraploid seed was increased with 35.6%; the increase in carvone amounted to 6.9%. The results of the experiment indicate that breeding work in autotetraploid caraway may result in a new cultivar.     

Transfer of the Rsv3 locus from ‘Harosoy’ for resistance to soybean mosaic virus strains C and D in Japan

Resistance to soybean mosaic virus (SMV) is imperative for soybean (Glycine max (L.) Merr.) production in the Tohoku region. Molecular markers for SMV resistance were previously reported for U.S. SMV strains, but they cannot be applied because of the differences in strain classification between Japan and the U.S. A U.S. variety ‘Harosoy’ has been used mainly as a donor of resistance to SMV strains C and D in a Japanese breeding program, resulting in resistant varieties such as ‘Fukuibuki.’ Because ‘Harosoy’ harbors the Rsv3 gene conferring resistance to the virulent SMV strain groups, G5 through G7, it appears that the Rsv3 gene confers resistance to strains C and D. In this study, we introduced resistance to the two strains from ‘Fukuibuki’ into a leading variety ‘Ohsuzu’ by recurrent backcrossing with marker-assisted selection. All lines selected with markers near Rsv3 showed resistance to the strains, suggesting that the Rsv3 locus is responsible for the resistance. Three years of trials showed that one of the breeding lines, ‘Tohoku 169,’ was equivalent to ‘Ohsuzu’ with respect to agricultural characteristics such as seed size, maturity date, and seed yield, except for the SMV resistance.     

Yield trade-off and the role of parental selection based on seed size when breeding for soybean seed protein

Alternative physiological strategies can increase protein concentration in soybean: (i) more-than-proportional increases in seed protein content (mg seed⁻¹) relative to increases in carbohydrate and oil content in large-seeded genotypes or (ii) more-than-proportional reductions in carbohydrate and/or oil content relative to protein content reductions in small-seeded genotypes. Because these strategies differentially affect crop growth and development, we hypothesized that populations developed from high-protein (HP) parents with contrasting seed sizes will present differences in how seed yield and protein concentration correlate. To test this, three breeding strategies were developed by mating high-yielding cultivars and HP ones that differ in seed sizes, reflecting the alternative strategies mentioned above. Neither tested crossing strategies showed differences in their correlation values between seed yield and protein concentration, as initially expected. Nevertheless, populations developed from crossing a HP-small-seeded parent to a HP-large-seeded one showed the highest number of transgressive segregants for protein yield. Our results showed that parent selection based on seed size has no beneficial effects on the development of high-yielding, HP soybean populations, but it might affect the number of transgressive segregants for protein yield.     

陆地棉双隐性核雄性不育系ms5ms6花药发育过程的研究

 利用石蜡切片技术从胚胎学方面对其进行研究,发现陆地棉双隐性核雄性不育系ms₅ms₆花药的败育时期是在花粉母细胞时期和小孢子发育期,以小孢子发育异常为主。败育特征为：花粉母细胞时期有少量核仁穿壁现象,还有部分小孢子母细胞出现半月形。小孢子时期出现小孢子粘连和少量的五分体,小孢子都没有刺突长出,最后解体、退化。不育花药和可育花药的绒毡层无明显差异,但不育花药的绒毡层分泌胼胝质的功能不正常。     

吉林省82年来育成大豆品种的产量和叶片部分生理特性变化及其相互关系

对吉林省1923—2005年间育成的42个大豆品种叶片部分生理特性及其与产量关系的研究表明, 大豆产量随育成年代的推进呈线性增加, 82年增加了95.94%, 平均每年增加1.17%; 与此同时, 叶片硝酸还原酶活性、可溶性糖含量、比叶重、叶绿素含量、可溶性蛋白含量均随年代推进而增加, 且与产量呈正相关; 在V₄期(第4节期, 主茎第3个复叶全展), R₂期(盛花期), R₄期(结荚盛期), R₆期(鼓粒盛期)等不同生育时期的生理指标变化不同, 把它们作为选择高产品种的参考指标具有一定的应用价值; 硝酸还原酶活性在V₄期、R₂期、R₆期与产量呈极显著正相关, 在所有指标中表现最稳定, 作为高产品种的选育指标最具可行性。     

Improvement in hydroxy fatty acid seed oil content and other traits from interspecific hybrids of three Lesquerella species: Lesquerella fendleri , L. pallida, and L. lindheimeri

Interspecific hybridization offers potential to improve the hydroxy fatty acid (HFA) content of lesquerella. Lesquerella fendleri is currently being developed for cultivation as a potential new industrial oilseed crop because of its seed productivity. However, it has lower HFA content compared to L. pallida and L. lindheimeri. The objectives of this research were to improve the HFA oil content of L. fenderi through interspecific hybridization and to characterize hybrids and successive generations for seed oil fatty acid profile, fertility, seed set and other morphological traits. In this work, three species were successfully hybridized, self-pollinated, and backcrossed. Ovule culture was used in some cases to produce progeny where interspecific hybrids did not produce viable embryos. The traits measured were petal length, ovules per silique, seeds per silique, and weight of 1000 seed. Patterns of leaf trichomes were used to distinguish between parents and hybrids. Seed per silique indicated that autofertility occurred in L. pallida but not in the other two species. HFA oil content of L. fendleri seed were 50.5% compared to 80 and 84% for L. pallida and L. lindheimeri, respectively. The HFA oil content of the hybrids ranged from 57 to 70% in A₂ and A₃ generations, and the range of values depended on the parents used in the crosses. These measurements will help predict the value of different interspecific crosses for breeding. Segregation for various yield related traits should allow selection for favorable improvements in the HFA trait and in seed yield.     

Genotype-environment interaction effects in F1 barley hybrids

Summary Genotype-environment interactions in F₁ hybrids between a selection of current commereial varicties as male parents and a balanced tertiary trisomic male-sterile female were investigated. Sixteen environments were employed, comprising eight treatments in each of two seasons. Hybrid stabilities in terms of yield response to changing environments, were found to be very similar to those of the parents, however hybrid yields exceeded parental yields in all but one instance. A heterotic effect for plant height was also observed.     

Molecular loci associated with seed isoflavone content may underlie resistance to soybean pod borer (Leguminivora glycinivorella)

Soybean pod borer (SPB) (Leguminivora glycinivorella (Mats.) Obraztsov) causes severe loss of soybean (Glycine max L. Merr.) seed yield and quality in some regions of the world, especially in north‐eastern China, Japan and Russia. Isoflavones in soybean seed play a crucial role in plant resistance to diseases and pests. The aim of this study was to find whether SPB resistance QTL are associated with soybean seed isoflavone content. A cross was made between ‘Zhongdou 27’ (higher isoflavone content) and ‘Jiunong 20’ (lower isoflavone content). One hundred and twelve F_5:10 recombinant inbred lines were derived through single‐seed descent. A plastic‐net cabinet was used to cover the plants in early August, and thirty SPB moths per square metre were put in to infest the soybean green pods. The results indicated that the percentage of seeds damaged by SPB was positively correlated with glycitein content (GC), whereas it was negatively correlated with genistein (GT), daidzein (DZ) and total isoflavone content (TI). Four QTL underlying SPB damage to seeds were identified and the phenotypic variation for SPB resistance explained by the four QTL ranged from 2% to 14% on chromosomes Gm7, 10, 13 and 17. Moreover, eleven QTL underlying isoflavone content were identified, and ten of them were encompassed within the same four marker intervals as the SPB QTL (BARC‐Satt208‐Sat292, Satt144‐Sat074, Satt540‐Sat244 and Satt345‐Satt592). These QTL could be useful in marker‐assisted selection for breeding soybean cultivars with both SPB resistance and high seed isoflavone content.