HMW-GS标记辅助选育优质小麦新品系

为加速优质小麦育种进程,将聚合杂交、HMW-GS辅助选择与常规育种程序结合,在小麦品种烟农19、济麦20、郑优6号、百农66不同杂交组合F2代进行HMW-GS标记辅助选择,经连续多代鉴定筛选,选育出14个含优质HMW-GS或HMW-GS组合的小麦新品系.鉴定结果表明,14个新品系的蛋白质含量、沉降值、湿面筋含量、面筋指...     

Genetic gain of Al tolerance and contribution of agronomic traits on Al tolerance in the early stage of sorghum breeding program

ABSTRACT

Genetic gain (GG), heritability and contribution of the agronomic traits on Al tolerance are precious information for selection strategy in the breeding of Al-tolerant sorghum. The objectives of this study were (i) to estimate the GG of Al tolerance in sorghum and (ii) to determine the direct effect of agronomic traits on Al tolerance through path analysis. Evaluation of agronomic characters used F₂, and F₃ sorghum progenies in field experiment and screening of Al tolerance used the hematoxylin-staining method. Three sorghum populations showed the low GG of Al tolerance (GG = 0.558–1.108). This result indicates that high allocation of progenies in the early stages of the Al-tolerant breeding program and high selection differential (sd) of Al tolerance should be applied to obtain a higher gain of Al tolerance. Selection pressure for early maturity (sd = ?2.942) and short plant height (PH) (sd = ?38.165) resulted in lower improvement of GG for Al tolerance. The high dry weight and tall PH provided a more genetic contribution to the advancement of Al tolerance. Based on the overall path analysis data, the increase of plant biomass, the significant number of progenies in the early stage of breeding and strong sd of Al tolerance would be more appropriate to improve the Al tolerance in sorghum.     

玉米品种先玉335的血缘系谱及主要农艺性状遗传分析

利用先玉335品种(PH6WC×PH4CV)P1、P2、F_1、B1、B2、F2共6个世代,运用主基因+多基因遗传模型和六世代联合分析方法,进行农艺性状株高、穗位高、穗重、穗粒重、穗轴重、穗长、穗行数、秃尖长、百粒重、出籽率的遗传分析。结果表明,株高、穗重、穗粒重、穗轴重、穗长、穗行数6个性状均为2对主基因加、显、上+多基因加、显混合遗传模型;秃尖长、百粒重两个性状为2对主基因加、显、上+多基因加、显、上混合遗传模型;穗位高为1对主基因加性+多基因加、显混合遗传模型;出籽率为多基因加、显、上遗传模型。株高、穗轴重、百粒重以主基因遗传为主、多基因遗传为辅。穗重、穗粒重、穗行数以主基因遗传为主;穗长主基因遗传、多基因遗传同等重要;秃尖长以多基因遗传为主,主基因遗传为辅;穗位高、出籽率多基因起决定作用。     

玉米纹枯病抗性的主基因+多基因混合遗传分析

利用自交系CML429(高抗)、CI23(中抗)、DM9(高感)和478(高感)组配得到6对正反交组合以及抗感组合CML429×DM9的P₁(CML429)、P₂(DM9)、B₁、B₂、F₁和 F₂ 6个世代材料进行玉米纹枯病抗性鉴定,研究分析这些抗感组合的抗性遗传特性。结果表明：玉米纹枯病抗性基本不存在胞质效应,抗性遗传符合两对加性-显性-上位性主基因+加性-显性-上位性多基因遗传模型;主基因间表现为加性-显性-上位性作用,两对主基因的加性效应分别为-1.228 4和-1.228 4,显性效应分别为-0.206 5和-0.206 3,其遗传效应值大小基本相同,且两对主基因间的加性效应与显性效应互作的上位性效应也相差不多,分别为0.293 1和0.293 5,两对主基因的遗传效应基本相同。抗感组合不同世代中F₂的主基因遗传率最高(70.22%);多基因遗传率在B₂最高(10.17%)。因此,在F₂的选择效率最高。     

Transgressive variants for red pericarp grain with high yield potential derived from Oryza rufipogon × Oryza sativa: Field evaluation, screening for blast disease, QTL validation and background marker analysis for agronomic traits

Five transgressive variants (advanced breeding lines from BC₂F₅ and BC₂F₆ generation) were derived from a cross between the wild relative, O. rufipogon Griff. and O. sativa L. subsp. indica cv. MR219, a popular high yielding Malaysian rice cultivar. The aim of the study was to evaluate the pericarp colour of the grains along with yield potential and to validate quantitative trait loci (QTLs) for agronomic traits. The variants were screened against blast disease. Background marker analysis was also done for the promising variants. The field trials were carried out at a single location (due to containment purposes) over two seasons using randomized complete block design (RCBD) with three replications. A trait-based marker analysis was used to identify QTLs for validation in BC₂F₅ generation. Analysis of variance (ANOVA) showed that the seasonal factors influenced different agronomic traits. Variant G33 produced significantly (p < 0.05) higher yield (5.20 t/ha) than the control, MR219 (4.53 t/ha). Eighteen QTLs for different agronomic traits were identified in BC₂F₂ population in a previous study. Among them 14 QTLs were found in BC₂F₅ population of the present study. The yield of variant G33 was influenced by several QTLs viz. qGPL-1, qSPL-1-2, qSPL-8 and qYLD-4, which were introgressed from the donor parent revealed by background marker analysis using BC₂F₇ generation. Percentage (99%) of red pericarp grain of G33 and G34 in BC₂F₅ and BC₂F₆ generations indicated the stability of pericarp colour which was transferred from the wild relative. Variant G33 showed resistance against two pathotype of blast disease (Magnaporthe oryzae). Among the evaluated variants, G33 could be considered for inclusion in the cultivar development program for red rice with high yield potential and resistance to blast disease. This study demonstrated that the alleles from wild relative could improve the yield and yield related traits through allelic interaction, even though the phenotypic traits were inferior to the recurrent parent.     

Gene effects for cotton-fiber traits in cotton plant (Gossypium hirsutum L.) under Verticillium conditions

Verticillium wilt (VW), caused by Verticillium dahliae Kleb., has become one of the most serious problems in cotton (Gossypium hirsutum L.). The use of resistant cultivars has long been considered the most practical and effective means of control. The objective of this work was to study the quantitative genetic basis of fiber traits under Verticillium conditions in upland cotton by using five genotypes and their possible crosses without reciprocals, selecting simultaneously for quality fiber, resistance, and agronomic characteristics. Five cotton cultivars and 10 F₁s from half diallel crosses were analyzed for quality fiber under VW conditions. The fiber length, uniformity, strength, elongation, and micronaire were measured during two crop seasons at two different sites each year, consistently in plots with soil naturally infested with Verticillium. Genetic components of variance were analyzed using the Hayman model. Analysis of variance for all traits showed significant differences between genotypes, with the genotype–site interaction in most of the studied traits except for fiber length and micronaire. Both the additive genetic variance component (D) and dominance genetic variance components (H1 and H2) were present in all traits. D was the most important component for uniformity, strength, elongation, and micronaire. Elongation was the trait most correlated with seed-cotton yield. Strength and micronaire were the traits most correlated with VWI. Broad-sense heritability was high for all the traits studied. Narrow-sense heritability was high for uniformity, strength and elongation, and moderate for length and micronaire.     

小麦农艺性状的主基因+多基因遗传分析

为明确小麦重要农艺性状的遗传组成,并筛选适于QTL的性状,以西农817和中国春为亲本,构建F2、F3群体,采用P1、P2、F1、F2、F3五世代联合分析方法,研究了株高、有效分蘖、小穗数、穗粒数、穗长、穗下节间距、小穗着生密度等产量相关性状的遗传模型.结果表明,7个性状不仅受基因的控制,同时也受到不同程度的环境影响.其中,穗长、穗粒数符合多基因遗传模型,无主基因存在;株高、小穗数、小穗着生密度符合一对加显性主基因+加性-显性多基因混合遗传模型;穗下节间距符合一对完全显性主基因+加性-显性多基因模型;有效分蘖符合一对负向完全显性主基因+加性-显性多基因模型.     

玉米品种通育189的雄穗分枝数F1平均优势及遗传分析

针对PH6WC、PH4CV、B20、D1279及PH6WC×PH4CV、PH6WC×B20、PH6WC×D1279、D1279×PH6WC鉴定试验进行雄穗分枝数差异分析,PH6WC×D1279(通育189)组建6世代群体(P₁、P₂、F₁、B₁、B₂、F₂),运用主-多基因混合模型遗传分析方法对雄穗分枝数遗传进行分析。结果表明,通育189雄穗分枝数存在细胞质遗传效应,F₁雄穗分枝数平均优势为28.57%～132.41%;雄穗分枝数遗传模型为2对主基因加、显、上+多基因加、显混合模型,2对主基因为正向完全显性,主基因上位性效应>显性效应>加性效应;主基因效应是多基因效应的41.25倍,主基因遗传率为27.58%～88.87%,多基因遗传率为0～41.78%。     

一个玉米无叶舌突变体Y43的遗传分析

在EMS法构建的玉米骨干自交系昌7-2突变体文库中,发现了一个玉米无叶舌突变体,随后通过连续自交,获得了纯合一致、稳定遗传的无叶舌自交系,命名为Y43。该突变体穗上部叶片直冲,表现为无叶舌,其他农艺性状与受体一致。通过对Y43与昌7-2及海9-21的F1、F2、BC1分析,初步确定该突变体无叶舌性状受一对隐性单基因控制。     

节节麦大穗大粒相关农艺性状的遗传分析

节节麦(Aegilops tauschii,DD)是六倍体普通小麦D基因组的祖先,其自然类群中含有丰富的抗逆、高产基因,利用其与四倍体硬粒小麦合成的六倍体小麦在现代小麦育种中得到了愈来愈多的应用。本课题在野生节节麦类群中发现了大穗、大粒材料AT462,利用其作母本与节节麦材料AT18(强分蘖)杂交;构建了F2、F3群体,通过调查亲本和群体单株的穗长、小穗数、粒长、粒宽和粒重等表型,对这些穗部性状进行了相关性分析和遗传分析。结果表明:(1)在F2和F3群体中,粒重、粒长与穗长之间不存在显著相关性,而且穗长与粒宽之间在两个群体中的平均相关系数绝对值小于0.1,粒重与小穗数之间的相关系数绝对值小于0.2,表明节节麦大粒相关性状不受穗长的影响,受小穗数影响也较小;(2)采用F2单世代分离分析的方法对节节麦AT462×AT18的F2群体大穗、大粒相关性状进行遗传分析,其中穗长受2对具有加性效应的主效基因控制;粒重和小穗数均同时受2对基因的加性效应、显性效应以及互作效应控制,其中加性效应占主导地位;粒长、粒宽均受2对基因的加性效应、显性效应以及互作效应控制,且三种效应较为均衡。这说明控制节节麦粒重、穗长、小穗数等产量性状相关基因的加性效应在遗传中占主导地位,在育种中较易利用,且其主效基因的遗传力达0.9。     

Insect-mediated cross-pollination in soybean [Glycine max (L.) Merrill] : I. Agronomic performance

In soybean, manual cross-pollination to produce large quantities of F₁ hybrid seed for yield trials is difficult and time-consuming. Conversely, insect-mediated cross-pollination has been shown to produce large quantities of hybrid seed in soybean and could facilitate the identification of heterotic patterns. The objective of our study was: (1) evaluate F₁ hybrid soybean plants from single crosses for yield and agronomic traits over several environments and (2) compare hybrid performance of the single crosses to lines developed from three-way crosses and backcrosses. In 2003, F₁ seed of single-crosses and their parent lines were evaluated in replicated experiments at three locations. Also in 2003, three-way crosses, and BC₁F₁ seed were produced. In 2004, three-way crosses, BC₁F₁ crosses, and their parent lines were evaluated at one location. High-parent heterosis (HPH) in single-crosses for grain yield ranged from −41.11% to +11.19%; for protein content from −4.34% to +3.53%, and for oil content from −13.22% to −0.84%. In three-way crosses, HPH for yield ranged from −25.21% to −4.50%, for protein from −2.72% to +1.92%, and for oil from −5.87% to −1.20%. For BC₁F₁ crosses, HPH for yield ranged from −15.65% to +41.97%, for protein from −2.57% to +1.69%, and for oil from −2.47% to +2.22%. Although positive heterosis levels were observed across all populations tested to determine the economic feasibility it is imperative that more tests of more cross-combinations be evaluated in replicated environments. Extensive research in different environments must be conducted to determine what parental combinations will produce the highest heterosis levels, and to develop criteria for selecting the parents with the best combining ability. This will be important to maximize agronomic performance that can economically justify the use of hybrids in soybean production.     

Variability in physicochemical and nutritional quality traits of parents,F2 and F3 generations of lentil crosses

Ten physicochemical and nutritional quality traits (100-seedweight, seed volume, seed density, bulk density, hydrationcapacity, hydration index, swelling capacity, protein, tryptophanand energy value) were examined in the seed samples of parents,F₂ and F₃ generations of three microsperma ×microsperma and two microsperma × macrospermacrosses of lentils. Significant variation for different traits wasobserved among the genotypes in both the groups and also amongboth types of crosses in F₂ and F₃ generations. Ranges,means and coefficients of variation (CV %) for various traitsamong parents, F₂ and F₃ generations of different crosses,along with the deviations between F₂ and F₃ generationmeans for various traits in different crosses are discussed. Alsosuggested is a breeding strategy for evolving lentil varieties withimproved seed yield and nutritional quality parameters.     

玉米低钾耐性性状的主基因+多基因遗传分析

应用植物数量性状主基因+多基因混合遗传模型多世代联合分析方法,以玉米缺钾症状叶片数为指标,对1个耐低钾玉米自交系T和2个低钾敏感玉米自交系S1和S2配制成的2个组合的P1、P2、F1、B1、B2和F2世代进行遗传分析,研究明确玉米耐低钾性状的遗传机制。结果表明,玉米低钾耐性遗传在2个组合中都由1对加性+加性-显性多基因控制;主基因遗传率(F2)平均为60.43%,多基因遗传率(F2)平均为15.35%;T×S1组合的遗传变异占表型变异值为80.20%,T×S2组合的遗传变异占表型变异值为71.35%,表明耐低钾性状以主基因遗传为主。育种应用上可以在低世代进行这一目标性状的选择。     

Heritability of,and genotypic correlations between,aflatoxin traits and physiological traits for drought tolerance under end of season drought in peanut (Arachis hypogaea L.)

More rapid progress in breeding peanut for reduced aflatoxin contamination should be achievable with a better understanding of the inheritance of, aflatoxin trait and physiological traits that are associated with reduced contamination. The objectives of this study were to estimate the heritability of aflatoxin traits and genotypic (r_G) and phenotypic (r_P) correlations between drought resistance traits and aflatoxin traits in peanut. One hundred-forty peanut lines in the F_4:6 and F_4:7 generations were generated from four crosses, and tested under well-watered and terminal drought conditions. Field experiments were conducted under the dry seasons 2006/2007 and 2007/2008. Data were recorded for biomass (BIO), pod yield (PY), drought tolerance traits [harvest index (HI), drought tolerance index (DTI) of BIO and PY, specific leaf area (SLA), and SPAD chlorophyll meter reading (SCMR)], and aflatoxin traits [seed infection and aflatoxin contamination]. Heritabilities of A. flavus infection and aflatoxin contamination in this study were low to moderate. The heritabilities for seed infection and aflatoxin contamination ranged from 0.48 to 0.58 and 0.24 to 0.68, respectively. Significant correlations between aflatoxin traits and DTI (PY), DTI (BIO), HI, biomass and pod yield under terminal drought conditions were found (r_P = −0.25** to 0.32**, r_G = −0.57** to 0.53**). Strong correlations between SLA and SCMR with A. flavus infection and aflatoxin contamination were also found. Positive correlations between SLA at 80, 90, and 100 DAP and aflatoxin traits were significant (r_P = 0.13** to 0.46**, r_G = 0.26** to 0.81**). SCMR was negatively correlated with aflatoxin traits (r_P = −0.10** to −0.40**, r_G = −0.11** to −0.66**). These results indicated that physiological-based selection approaches using SLA and SCMR might be effective for improving aflatoxin resistance in peanut.     

Generation mean analysis of pearl millet [Pennisetum glaucum (L.) R. Br.] grain iron and zinc contents and agronomic traits in West Africa

Pearl millet is the most important staple food crop for millions of people across the world. Micronutrient malnutrition is the major problem for people living in the semi-arid regions of Africa. Identification of gene effects controlling the inheritance of grain Fe and Zn will be helpful in formulating suitable breeding strategies for biofortified pearl millet development. Hence, generation mean analysis was used to study epistasis and estimate gene effects for grain iron and zinc contents along with the agronomic and morphological traits. Six generations P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂ were generated and were evaluated during the 2018–19 off season. Analysis of variance showed significant variability for all the traits in both generations. Six parameter model revealed predominance of additive gene effects for inheritance of grain iron concentration, and additive × additive type of non-allelic interactions. For grain zinc concentration additive gene effects were preponderant compared to non-additive gene effects, and only additive × dominance gene effects were significant among the three types of epistasis. Grain weight per plant was predominantly under non-additive gene effects and additive × additive and additive × dominance gene effects type of epistasis was detected in each cross. Likewise, for flowering non-additive gene effects were most important with the presence of dominance × dominance type of epistasis. For plant height, panicle circumference and length, additive × additive genes effects were the most important among the three type of non-allelic gene action.These findings can be helpful in enehancing the pearl millet breeding programs in Africa.     

分子标记辅助选择下的玉米回交群体农艺性状分析

以综3为受体亲本、衡白522为供体亲本,通过3代回交,利用SSR标记对BC3F1群体背景进行检测,并进行群体植株重要农艺性状的分析。结果表明,群体背景回复率在94.40%以上,平均回复率为97.75%,最高回复率为100%,远远高于经典遗传学背景回复率。农艺性状分析结果显示,背景回复率并未达到分子标记结果。分子标记辅助选择是提高育种选择效果加速育种进程的有效途径之一,针对数量性状控制的农艺性状的选择还需要进一步研究。     

Genetic Variability for Grain Yield and Its Components in an Early Tropical Yellow Maize Population Under Striga hermonthica Infestation

Abstract

A major problem that usually confronts the breeder is ensuring that there is sufficient genetic variability in a population for the trait being improved because this determines the breeding schemes to use for improvement and whether or not sufficient progress could be made. Three hundred full-sib families from cycle 3 of the early maturing yellow endosperm maize (Zea mays L.) population, TZE-Y Pop DT STR, were evaluated under artificial Striga hermonthica infestation at Mokwa and Abuja, Nigeria in 2003. The objectives of this study were to investigate the type of gene action involved in the inheritance of S. hermonthica resistance in TZE-Y Pop DT STR C3, determine the extent of genetic variability available in the population after three cycles of S1 recurrent selection, and the phenotypic and genetic correlation coefficients among the traits used for selecting for resistance to S. hermonthica. Estimates of dominance variances were larger than additive genetic variances for grain yield, plant height, ear height, number of ears at harvest, and Striga damage rating at 8 weeks after planting (WAP). Even though h2 estimates were generally low for most traits (< 0.40), moderate-to-large additive genetic variances, and wide ranges were obtained in TZE-Y Pop DT STR C3 for most traits, suggesting that there was adequate genetic variation for improving Striga resistance and grain yield in the population. Highly significant phenotypic correlation coefficients were obtained between grain yield and ears per plant, plant height, ear height, days to anthesis and silking, anthesissilking interval, and Striga damage score at 10 WAP. Recurrent selection methods that capitalize on both additive and dominance variances would be effective for improving the population for Striga resistance and grain yield.     

利用CIMMYT资源创制小麦抗病及农艺新种质的研究

为利用CIMMYT资源创制小麦抗病、农艺性状优良的新材料,以CIMMYT新培育的RL6077与西农979、周麦27等骨干品种进行冬春性杂交和(或)回交,构建RIL群体和有限回交群体;以CIMMYT材料Wheatear与豫农982进行冬春性杂交构建F2:7RIL群体。应用特异性分子标记对这些群体材料进行分子检测,同时进行田间抗病性鉴定和农艺性状选择。结果表明,RL6077后代群体的众多性状都介于两个亲本之间,很好地遗传了双亲的农艺特征;其RIL群体中更易检测到抗病基因,回交群体后代更易选出农艺性状优良的品系,可根据育种目标选用合适的群体;本研究选育出冬性、农艺性状优良且具有抗病基因(抗Ug99)的储备性新品系6份。Wheatear/豫农982的F2:7RIL群体中,1BL/1RS易位系的千粒重和叶宽显著高于非易位系;7DL·7Ag易位对穗下节长和穗粒数具有正向作用;双易位系则综合了上述特性;经田间抗病性鉴定,易位系具有良好的综合抗病性;从此群体中选育出冬性、双易位且农艺性状优良的新品系4份。     

玉米子粒油分含量的遗传模型分析

玉米子粒油分含量直接影响着深加工品质,研究子粒油分含量的遗传模型,可以为遗传育种中进一步提高玉米油分含量提供参考。以3个玉米组合济533/PH6WC、济533/H5818和2394/PH4CV的亲本构建各自的六世代群体(P1、P2、F_1、B1、B2、F_2),利用主基因+多基因混合遗传模型分析玉米子粒油分含量的遗传特性。结果表明,3个组合油分含量均符合D-2模型(1对加性主基因+加性-显性多基因模型),主基因+多基因遗传率均以F_2代较高,表明玉米子粒油分特性在F_2世代选择时效率较高。     

玉米F1、F2代穗粒性状的遗传效应分析和适宜群体筛选

利用2个优良爆裂玉米自交系与6个Reid类群普通玉米自交系杂交组配12个杂交组合,研究穗长、穗粗、穗行数、行粒数、百粒重、穗重、穗粒重和出籽率8个穗粒性状的F1表现、杂种优势和F2群体表现、分离特征及其与亲本的相关性。结果表明,不同组合F1表现、中亲优势(MH)、超高亲优势(HH)和F2群体的平均值(F2M)、变幅、变异系数、优势衰退(HDR)等均存在不同程度差异,各穗粒性状杂交早代的遗传背景效应突出;F2群体各性状均呈连续正态分布,存在超双亲分离,为多基因控制的复杂数量性状;杂种优势较小的穗行数、出籽率和穗粗可以根据两类亲本或其均值初步预测其组合F1和F2M值的表现,对于杂种优势较大的穗重、穗粒重和百粒重不宜进行预测;除穗行数和出籽率外,其余性状F1表现与F2M、MH和HH以及F2M、MH、HH间多呈显著或极显著正相关,HDR与F1、F2M、MH和HH均呈显著或极显著负相关;R2×N04、R4×N10和R5×N10组合为进一步开展遗传作图和改良爆裂玉米自交系穗粒性状的最佳群体。