Seed yield and its components of indeterminate and determinate lines in recombinant inbred lines of soybean

The present study was conducted to evaluate the benefits of indeterminate growth habit in breeding to improve yield potential of Japanese soybean varieties, which exclusively have determinate growth habit. Two populations of recombinant inbred lines (RILs) derived from crosses between determinate Japanese cultivars and indeterminate US cultivars were grown in Akita and Kyoto, and seed weight per plant (SW) and its components were compared between indeterminate and determinate RILs. The difference of SW between the two growth habits in RILs varied depending on maturation time. The SW of early indeterminate lines was significantly higher than that of early determinate ones in Akita, but not in Kyoto. Among yield components, the number of seeds per pod was constantly larger in indeterminate lines than that in determinate ones irrespective of maturation time. The number of seeds per plant and the number of pods per plant of the indeterminate lines were greater than those of the determinate lines in early maturation in Akita. These results suggest that the indeterminate growth habit is an advantageous characteristic in breeding for high yield of early maturing soybean varieties in the Tohoku region.     

Characterization and identification of cold tolerant near-isogenic lines in rice

To exploit the genetic mechanism of cold tolerance in rice, cold tolerant near-isogenic lines (NILs) were developed by backcrossing Kunmingxiaobaigu (KMXBG), reported to be the most cold-tolerant variety at the booting stage, as donor, with the cold sensitive Japanese commercial japonica variety, Towada. Comparisons of cold tolerance-related traits between five BC₆F₅ NILs and recurrent parent Towada under cold treatment and normal temperatures at the booting stage showed that the differences between the NILs and Towada were significant only for spikelet fertility-related traits. Analyses of cold tolerance in the NILs at the budding (germination), seedling and booting stages indicated both correlated effects and differences. Lines 1913-4 and 1916-1 showed strong and stable tolerance at all three stages. Whole genome marker screening showed that the proportion of genetic background recovery was more than 98%. Seventeen markers from KMXBG were introgressed in two or more NILs, and cold tolerance genes were possibly present in these marker regions. The NILs should be excellent materials for both rice improvement and map-based cloning of cold tolerance QTLs.     

发展杂交棉三系不育系的必要性和可能性

<正>我国杂交棉种植面积逐年扩大,长江流域棉区基本全部种植杂交棉,黄河流域棉区杂交棉种植面积达30%左右,新疆棉区也在积极推广杂交棉种植。但目前杂交棉种的生产成本逐年上升,销售价格逐年下降,种子生产、销售各环节的利润越来越少,发展三系不育系制种是解决目前困境的有效方法。     

Stripe rust resistance and genes in Chinese wheat cultivars and breeding lines

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases on wheat in China. To assess resistance in wheat cultivars and breeding lines in China, 330 leading cultivars and 164 advanced breeding lines were evaluated with stripe rust. In the greenhouse tests, seedlings of the entries were inoculated separately with several Pst pathotypes. In the field tests, the entries were evaluated for stripe rust resistance in Yangling, Shaanxi Province artificially inoculated and in Tianshui, Gansu Province under natural infection of Pst. The oversummering/wintering and spring epidemic zones of resistance genes were postulated using molecular markers for Yr5, Yr9, Yr10, Yr15, Yr17, Yr18, and Yr26, in combination with resistance spectra. Out of the 494 wheat entries, 16 (3.24 %) entries had all-stage resistance (ASR) in all race tests, 99 (20.04 %) had adult-plant resistance (APR), 28 (5.67 %) were considered to have slow-rusting (SR), and 351 (71.05 %) were susceptible to one or more races in both seedling and adult-plant stages. Advanced breeding lines had a higher percentage (37.2 %) of resistant entries (The sum of ASR, APR and SR) than leading cultivars (24.85 %). Among the epidemic regions, southern Gansu had a higher percentage of resistant entries than any other regions. Based on stripe rust reactions and molecular markers, two cultivars were found to possibly have Yr5 while no entries have Yr10 or Yr15. Resistance genes Yr9, Yr17, Yr18, and Yr26 were found in 134 (29.4 %), 45 (9.1 %), 10 (2 %), and 15 (3 %) entries, respectively.     

杀配子染色体及其在创制小麦族染色体易位系中的应用

山羊草属植物中的某些染色体,当其单体附加到小麦基因组时,能使带有该染色体的配子正常存活;而使无该染色体的配子发生染色体断裂,产生易位等染色体结构畸变。利用杀配子染色体创制易位系是将小麦近缘种属野生资源的优良性状转移给小麦的一个有效途径。本文介绍了杀配子染色体的类型、作用时期,并重点综述了利用杀配子染色体创制小麦族染色体易位系方面的研究进展。     

Responses to photoperiod before and after jointing in wheat substitution lines

It has been hypothesised that wheat yields may be increased by lengthening the duration of the stemelongation phase. This paper reports studies on the effects of chromosomes carrying major photoperiod genes (Ppd-A1, Ppd-B1, Ppd-D1) in different genetic backgrounds, on responses to photoperiod before and after jointing, when the onset of stem elongation occurs, and on number of grains per spike. A field experiment considered the effects of two photoperiods on Chinese Spring and 12 substitution lines, in which chromosomes 2A, 2B or 2D had been substituted by those from four contrasting cultivars. The phase from seedling emergence to jointing (EM-JO) was more responsive than that from jointing to anthesis (JO-ANT), but no relationship was found between the duration of these phases. EM-JO length affected leaf and spikelet number and consequently grains per spike, but this component was further influenced by JO-ANT duration. Our results confirmed that the phases are independent in sensitivity, supporting the hypothesis that genetic manipulation of phase duration could enhance yield, but no evidence was found of any particular Ppd allele being responsible for major responses to photoperiod during stem elongation. This revised version was published online in July 2006 with corrections to the Cover Date.     

豌豆优良品系引进与评价

通过引进国内外46个遗传稳定的豌豆优良品系进行筛选和评价,选定性状优异、适宜本地的品系,以便为本地豌豆生产和科研提供新品种。     

Genotyping-by-sequencing of waxy and glossy near-isogenic broccoli lines

Wild-type Brassica oleracea L. have matte blue-green leaves caused by an interaction between leaf pigmentation and a waxy bloom coating the surface. Glossy mutants have reduced and/or altered epicuticular wax giving the leaves a shiny green appearance and have been identified in most B. oleracea crop varieties, including cauliflower, kale, broccoli, Brussels sprouts, cabbage, and collard. The genetic basis of glossy mutants has not been studied in B. oleracea. Glossiness can confer resistance to multiple herbivores mediated by modification of herbivore feeding behavior and foraging efficiency of their predators. The USDA-ARS-U.S. Vegetable Laboratory released two pairs of near-isogenic broccoli lines (NILs) that visibly differ only for glossiness, providing ideal germplasm for the genetic study of epicuticular wax in B. oleracea. Genotyping-by-sequencing resulted in hundreds of polymorphisms between each pair of NILs. Polymorphisms were identified in or near three different wax synthesis genes suggesting the two glossy mutants were caused by alteration of different steps of the pathway.     

Inter-varietal chromosome substitution lines in wheat — revisited

Summary The difficulties in developing inter-varietal chromosome substitution lines in wheat are reviewed. The use of genetical, cytological and molecular markers is suggested as a way of overcoming them. These difficulties and the use of markers, as well as the need to develop duplicate lines to detect background variation, are described using the development and analysis of the Cappelle-Desprez (Bezostaya 1) chromosome substitution set as an example. The effects of substituting Bezostaya 1 chromosomes on final plant height and adult-plant resistance to yellow rust are reported. The large number of aneuploids and substitution lines available in wheat provides a tremendous, international resource, which should be exploited in the future.     

Comparisons between doubled haploid lines produced by anther culture,the Hordeum bulbosum-method and lines produced by single seed descent in barley crosses

Summary Possible negative effects of tissue culture on qualitative and quantitative characters have been investigated in three crosses of spring barley, using doubled haploid lines produced by anther culture (AC, with maltose as a carbon source) or the Hordeum bulbosum-method (HB). In one cross inbred lines produced by single seed descent (SSD) have also been included. Quantitative characters were investigated in a 2-year field experiment at one location. The results show that although the methods in the majority of cases gave similar results, the genotypic arrays produced were not identical. Different markers deviated in the various cross/method combinations. The ranking of methods as well as the frequencies of lines transgressive for grain yield differed between crosses. Thus no consistently negative impact of anther culture in barley has been found, and, although not identical, the various methods may be considered equivalent.Abbreviations AC Anther Culture method - SSD Single Seed Descent method - HB Hordeum bulbosum method     

Development of a DNA marker for distinguishing CMS lines from fertile lines in rice (Oryza sativa L.)

The main objective of the present study was to identify mitochondrial DNA based marker, which can distinguish male sterile and fertile counterparts of the cytoplasmic male sterile (CMS) lines used in production of rice hybrids. Amplified fragment length polymorphism (AFLP) analysis in CMS lines: IR58025A & IR62829A and their respective maintainers: IR58025B & IR62829B identified a polymorphic DNA fragment of about 510 bp size that was present in both CMS (A) and absent in their maintainer (B) lines. Sequencing followed by database analysis of the polymorphic fragment indicated about 97% similarity with mitochondrial NADH gene subunits of rice, maize and wheat. Based on the variable sequence regions, a site specific primer pair (BF-STS-401) was designed. PCR analysis showed that BF-STS-401 could amplify a strong band of 464 bp size in CMS and a faint band of the same size in maintainer line. To act as a positive control and avoid possible errors in PCR, BF-STS-401 was multiplexed with a new primer pair (BF-STS-402), derived from mitochondrial atp9 subunit of rice, producing monomorphic amplification indiscriminately in both CMS and maintainer lines. Both the primer pairs in combination clearly differentiated CMS lines from their corresponding maintainer lines. This primer combination was validated in a set of diverse genotypes consisting of different sources of CMS lines, restorer lines, hybrids, varieties and mixed samples from private seed companies. Our results suggested that the multiplex primer pairs developed in this study can be effectively utilized to assess the genetic purity in commercial seed lots of CMS lines and hybrids of rice.     

Genotypic differences in callus growth and organogenesis of eight pearl millet lines

Summary Calli were obtained from mesocotyl explants of eight varieties of pearl millet using MS medium supplemented with 2,4-D. Variable frequencies of callus initiation were observed among the varieties. Plantlets were regenerated from the calli by transferring on to the medium devoid of auxins. Incorporation of coconut milk, Kinetin, IAA or NAA did not enhance either the callus initiation or growth rate or plantlet regeneration. The eight genotypes differed among themselves in callus growth rate and frequency of shoot bud production.     

Inheritance and allelism of Russian wheat aphid resistance in several wheat lines

The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko) has caused serious reduction in wheat production in 17 Western states of the United States since 1986. Inheritance of resistance to RWA in seven wheat lines and the allelism of the resistance genes in these lines with three known resistance genes Dn4, Dn5, and Dn6 were studied. The seven resistant lines were crossed to a susceptible wheat cultivar ‘Carson’ and three resistant wheats: CORWA1 (Dn4), PI 294994 (Dn5), and PI 243781 (Dn6). Seedlings of the parents, F₁, and F₂ were screened for RWA resistance in the greenhouse by artificial infestation. Seedling reactions were evaluated 21–28 days after the infestation using a 1–9 scale. The resistance level of all the F₁ hybrids was similar to that of the resistant parent, indicating dominant gene control. Only two distinctive classes were present and no intermediate types were observed in the F₂ population, suggesting qualitative, nonadditive gene action, in which the presence of any one of the dominant alleles confers complete resistance to RWA. Resistance in CI 2401 is controlled by two dominant genes. Resistance in CI 6501 and PI 94365 is governed by one dominant gene. Resistance in PI 94355 and PI 151918 may be conditioned by either one dominant gene or one dominant and one recessive gene. No conclusion can be made on how many resistance genes are in AUSVA1-F₃, since the parent population was not a pure line. Allelic analyses showed that one of resistance genes in CI 2401 and PI 151918 was the same allele as Dn4, the resistance gene in CI 6501 was the same allele as Dn6, and AUS-VA1-F₃ had one resistance gene which was the same allele as one of the resistance genes in PI 294994. One non-allelic resistance gene different from the Dn4, Dn5, and Dn6 genes in CI 2401, PI 94355, PI 94365, and PI 222668 was identified and should be very useful in diversifying gene sources in wheat breeding.     

Genetic analysis of edamame seed composition and trait relationships in soybean lines

Edamame, a vegetable or specialty soybean (Glycine max) with high nutritional and market value, is relatively new to North America. Because of its health and nutritional benefits and globalized trade, the edamame market and acreage in the United States are steadily increasing. To facilitate edamame breeding and commercial production, we genetically analyzed edamame seed composition using 86 breeding lines and cultivars developed in the U.S. Significant genotypic differences based on a single year or 2-year joint analysis were observed for most traits investigated, including protein, oil, dietary fiber, starch, sucrose, stachyose and total sugar content. No significant genotypic difference was observed for ash content in both years and for raffinose content in year 2016. Yearly differences were also significant except for sucrose, stachyose and total sugar. Genotype-by-year interaction was significant for protein, sucrose, raffinose and total sugar, but insignificant for other traits. The heritability was high and relatively stable for protein and oil content, followed by stachyose content, but was low for ash and starch content. The heritability for sucrose, total sugar and dietary fiber content varied from 38 to 75%. Genotypic correlations were insignificant among most traits. However, protein content was negatively correlated with oil content and dietary fiber, but positively associated with stachyose. Oil content was negatively correlated with starch and individual sugars. Although positive phenotypic or Pearson’s correlation existed between total sugar content and individual sugars, and between sucrose and starch content, their genotypic correlations were insignificant.     

Genetic analysis of four self-incompatible lines in Brassica napus

Reciprocal hybridization between four self-incompatible lines of Brassica napus: 271, 181, 184 and ‘White Flower’, revealed incompatibility. The reciprocal F₁s obtained by bud pollination showed self-incompatible reactions, and no segregation for self-incompatibility was observed in all the reciprocal F₂ populations, indicating that lines 271, 181, 184 and ‘White Flower’ were genetically identical with regard to self-incompatibility. Observations of self-incompatibility in 17 hybrids from crosses between line 271 and 17 varieties of B. napus showed 10 of the F₁ hybrids to be self-compatible, while four were partially self-compatible and three were self-incompatible. Genetic analysis based on F₂ and BC₁ populations from five self-compatible F₁ hybrids and two self-incompatible F₁ hybrids suggested the existence of at least two loci controlling the self-incompatibility of line 271: one is the S locus, with dominant and recessive relationships between the S alleles, and the other is the suppressor (sp) of the S locus. The sp locus is genetically different from the S locus, and also shows dominant and recessive relationships between the sp alleles.     

杀配子染色体在小麦-黑麦异代换系中的作用研究

利用小麦-黑麦异代换系H-13(1R/1D), H-24(5R/5A),H-33(6R/6A)与中国春-杀配子染色体二体异附加系CS-DA2C(来自山羊草Ae. cylindrica),CS-DA3C(来自山羊草Ae. triuncialis)配置杂交组合,对杀配子染色体的作用进行了研究。结果表明,杀配子染色体3C对H-13和H-24都是致死的,即有着完全的杀配子作用,但对H-33的杀配子作用则是不完全的,有着接近正常的结实率,说明不同的小麦-黑麦异代换系遗传背景对杀配子作用有很大影响,可能在品系H-33中存在对2C染色体杀配子作用的抑制基因。在以品系H-33为母本时,2个杀配子附加系F1的自交结实率差异显著,说明在相同的小麦-黑麦异代换系遗传背景下,染色体2C与3C的杀配子作用是不同的,在这2个杀配子染色体上可能带有不同的杀配子基因?这些研究结果为进一步创制小麦-黑麦易位系奠定了基础。     

New early-maturing germplasm lines for utilization in chickpea improvement

Early-maturity helps chickpea to avoid terminal heat and drought and increases its adaptation especially in the sub-tropics. Breeding for early-maturing, high-yielding and broad-based cultivars requires diverse sources of early-maturity. Twenty-eight early-maturing chickpea germplasm lines representing wide geographical diversity were identified using core collection approach and evaluated with four control cultivars in five environments for 7 qualitative and 16 quantitative traits at ICRISAT Center, Patancheru, India. Significant genotypic variance was observed for days to flowering and maturity in all the environments indicating scope for selection. Genotypes × environment interactions were significant for days to flowering and maturity and eight other agronomic traits. ICC 16641, ICC 16644, ICC 11040, ICC 11180, and ICC 12424 were very early-maturing, similar to or earlier than control cultivars Harigantars and ICCV 2. The early-maturing accessions produced on average 22.8% more seed yield than the mean of four control cultivars in the test environments. ICC 14648, ICC 16641 and ICC 16644 had higher 100-seed weight than control cultivars, Annigeri and ICCV 2. Cluster analysis delineated three clusters, which differed significantly for all the traits. First cluster comprised three controls, ICCV 96029, Harigantars, ICCV 2 and two germplasm lines, ICC 16644 and ICC 16641, second cluster comprised 13 germplasm lines and control cultivar Annigeri, and third cluster comprised 13 germplasm lines. Maturity was main basis of delineation of the first cluster from others. Plot yield and its associated traits were the main basis for delineation of the second cluster from the others. Identification of these diverse early-maturing lines would be useful in breeding broad-based, early-maturing and high-yielding cultivars.