11份玉米自交系单株产量等性状的配合力与遗传参数研究

旨在研究玉米自交系单株产量等性状的配合力、遗传力及反交效应,为玉米自交系的选育和杂交种的组配提供依据。以11份玉米自交系为试材,按Griffing Ⅲ完全双列杂交法组配110个组合,观测杂交种的单株产量、株高、穗位高、雄穗分支数、雄穗主轴长、抽丝期和开花期等7个性状的表型数据,并对上述性状的一般配合力、特殊配合力、广义遗传力、狭义遗传力和反交效应进行估算。供试材料除雄穗主轴长的特殊配合力差异不显著外,其余性状的一般配合力和特殊配合力差异均达到极显著水平。JZ3和JZ6两个自交系单株产量的一般配合力为极显著正值,两对组合JZ9×JZ2和JZ2×JZ9、JZ6×JZ3和JZ3×JZ6的单株产量具有最大的正向SCA效应值,分别为40.68 g和35.24 g。单株产量的反交效应差异极显著,部分自交系的反交效应方差较大。7个性状的广义遗传力从大到小依次为,雄穗分支数、株高、开花期、穗位高、抽丝期、单株产量和雄穗主轴长;狭义遗传力从大到小依次为,雄穗分支数、株高、穗位高、开花期、雄穗主轴长、抽丝期和单株产量。试验结果表明单株产量性状的显性遗传方差占比最大,狭义遗传力最小,易受环境条件的影响,对该性状的选择适宜在晚代进行;单株产量性状具有显著的反交效应,故部分自交系需严格控制正反交方式。     

杉木育种中GCA与SCA的相对重要性

选取九个待测优树无性系（材料Ⅰ），进行９×９杉木半双列交配试验，以及采用经过生长性状方面ＧＣＡ测定评选出来的六个速生优良无性系（材料Ⅱ），进行６×６杉木全双列交配试验。杉木配合力分析结果表明：采用Ⅱ类材料，进一步进行遗传测定时，群体一般配合力（ＧＣＡ）方差σｇ２小于群体特殊配合力（ＳＣＡ）方差σｓ２；而采用Ⅰ类材料，进行遗传测定时则：σｇ２＞σｓ２。不同的试验得出不同的结果，这主要是由研究材料的性质决定的。在杉木遗传改良领域中，加性学说与显性学说其实并不矛盾，因为ＧＣＡ的测定与评选和ＳＣＡ的测定与评选之间具有相对的独立性     

玉米几个自选新系与几个常用系主要性状配合力及其相关性分析

对玉米5个自选新系与11个生产上常用的骨干自交系采用NCⅡ(11×5)配成55个杂交组合.对各组合的7个主要性状进行了配合力分析,同时对6个主要性状的GCA与单株粒重的GCA进行了相关分析.结果表明,襄7298、襄2178、襄706、襄329、Lx9801、PH6WC、郑58、Y8G单株粒重的GCA较高.是值得重点利用和改良的自交系材料.襄2178×襄7298、襄706×襄7298、PH6WC×襄7298、Y8G×襄7298、襄329×襄7298、9041×襄7298、襄4887×Lx9801、Lim50×襄7298、襄706×昌7-2、襄706×浚926为强优势组合.单株粒重GCA的增加是提高产量的重要基础.选育出单株粒重GCA较高的优良新系组配出高产杂交组合的可能性较大.穗长、行粒数、千粒重GCA的增加可以有效地提高单株粒重的GCA.     

Performance of upland coloured cotton germplasm lines in line × tester crosses

Anthracnose is a serious disease affecting dry bean production especially in the cool highland areas worldwide. The objective of this research was to study the inheritance of anthracnose resistance in market-class dry beans. A complete diallel set of crosses was generated from nine diverse parents comprising six resistant and three susceptible to anthracnose. The F₁ and F₂ crosses and parents were artificially inoculated with Colletotriclum lindenumthianum Race-767 in a growth room. There was significant variation for anthracnose resistance among genotypes. General combining ability (GCA) and specific combining ability effects were significant for resistance, indicating importance of both additive and non-additive effects, respectively. Preponderance of GCA effects (66%) suggested that additive effects were more important than non-additive effects (24%), which were also reflected by high heritability estimates (70%), and suggested that simple selection or backcrossing would be useful for improving the resistance in market class varieties. The study was not conclusive on whether epistatic gene action played a major role, but if available it might have biased the dominance gene effects. Reciprocal effects (10%) were not significant (P > 0.05), suggesting that cytoplasmic genes did not play a major role in modifying anthracnose resistance. Parental lines G2333, AB136, NAT002, and NAT003 showed highly negative GCA effects qualifying them as suitable parents for transferring resistance genes to their progenies. A few major genes, 1–3, displaying partial dominance conditioned anthracnose resistance, suggesting a possibility of using marker-assisted selection to improve anthracnose resistance in market-class dry beans.     

Lancaster群体改良自交系株型性状的配合力分析

采用不完全双列杂交,分析8个含有Lancaster血缘的自交系与4大类群代表系中5个自交系的一般配合力(GCA)和特殊配合力(SCA)。结果表明：株高、穗位高、茎直径、雄穗长、雄穗分枝的GCA和SCA方差均达极显著水平;一般配合力及小区产量较高的自交系有N305、N575、N583、吉853、丹340、丹988;N575×丹340的总配合力效应值最高,是最好的杂交组合。在供试的8个自交系中,N575、N583、N305与各父本所配杂交组合产量较高,是比较理想的自交系。株型性状间的相关分析表明,株高与穗位高、雄穗长度有较大的正相关,穗位高与茎直径相关性较大。     

Analysis of host plant resistance to multiple Fusarium species associated with stalk rot disease in sorghum [Sorghum bicolor (L.) Moench]

Fusarium spp. is among the largest and most important pathogen groups that attack major grain crops including sorghum. The objectives of this study were to compare the virulence of Fusarium spp. associated with sorghum and examine the mode of resistance of genotypes to the disease. Eight Fusarium species – F. verticillioides, F. thapsinum, F. andiyazi, F. proliferatum, F. nyagamai, F. pseudoanthophilum, F. brevicatenulatum, and F. pseudonygamai – were studied using three sorghum genotypes under greenhouse condition. Three of these pathogens (F. verticillioides, F. thapsinum, and F. andiyazi) were selected for genetic analysis of resistance under field conditions. Sorghum genotypes with contrasting stalk rot reactions were selected for use in both the greenhouse and field experiments. Two weeks after flowering, plants were inoculated with liquid inoculum culture (5 × 10⁴ conidia ml⁻¹) of the different pathogens. Plants were harvested 4 weeks after inoculation and rated for disease severity on the basis of lesion length and number of nodes crossed by the lesion. Among the pathogens, F. thapsinum resulted in consistently higher disease scores in all genotypes under all environments. Likewise, genotype SC599 showed the greatest and most stable resistance as inbred as well as in hybrid combinations as shown by consistently high GCA for resistance to all pathogen species. We recommend that future screening exercises for Fusarium stalk rot resistance utilize F. thapsinum as the causal organism and include the resistant genotype SC599 as a control.     

籼型三系杂交水稻产量及生育期的配合力分析

用4个湖南近年审定的三系不育系与湖南农业大学水稻所育成的具有代表性的5个籼型三系恢复系配组,采用p×q不完全双列杂交(NCⅡ),对获得的20个组合进行单株产量、生育期的一般配合力和特殊配合力效应以及杂种F1优势表现分析。结果表明:(1)单株产量、全生育期的一般配合力和特殊配合力均达显著或极显著水平,由可遗传的基因加性效应和不可遗传的非加性效应共同控制。(2)单株产量、全生育期的一般配合力和特殊配合力不育系三香A较好,恢复系以416较好。(3)亲本单株产量、全生育期的一般配合力与特殊配合力之间没有明显的对应关系。(4)综合评价20个杂交组合,三香优416、丰源A/283,丰源A/502有生产利用价值。     

杂交早稻亲本的评价和利用研究

以6个不育系作母本和7个恢复系作父本交叉配组的42个组合为材料,系统观测了产量性状、品质性状和生育期,分析了亲本的一般配合力和特殊配合力方差.根据试验结果,进行综合评价,并对其如何利用提出了建议.     

“中苜一号”紫花苜蓿耐盐遗传特性初步研究

以“中苜号”紫花苜蓿耐盐新品种为材料,应用ＮＣⅡ杂交试验方案,研究其耐盐遗传参数,旨在为今后苜蓿耐盐育种提供理论依据。结果表明,在直 迫下,苜蓿的干重、株高和分枝数诸性状的加性产应大于显性效应,狭义跗力较大,分别为０．４２５、０．３８７和０．４８４,具有通过选择进一步提高耐盐性的遗传潜力。