甘蓝型油菜杂交种亲本的遗传多样性评价

 利用SSR和ISSR分子标记对18份不育系、21份恢复系和11份对照品种共50份甘蓝型油菜进行了遗传多样性评价。UPGMA聚类结果显示,50份材料被聚为四大类群,其中所有的不育系聚在第四大类,恢复系都聚在了其它三大类中。不育系又分为2个亚类,其中核不育系聚为一亚类(除1471AB外),而所有的细胞质雄性不育系均聚为另一亚类。不育系间的遗传差异比恢复系间小。     

高产脂马尾松优树自由授粉子代林产脂力测定

通过高产脂马尾松自由授粉子代林,多年的产脂力测定结果,发现有75%的高产脂马尾松家系的产脂力高于普通马尾松.从子代林家系间的遗传分析结果,家系遗传力为67.48%遗传变异系数为0.725,遗传增益为68.33%.经亲—子间产脂力的相关分析,相关系数达到显著性水平r=0.616,预测回归方程为y=0.732x-2.903,回归方程方差分析结果达到极显著性水平.通过高产脂马尾松幼年—成年期产脂力间的累年测算结果,发现子代林和成熟林间的相关系数,随树龄增大而提高,而幼年—成年期的选择差百分数,随子代林年龄增大而减小.     

Genetic variation for resistance to Phytophthora fragariae var. rubi in red raspberries

Summary The inheritance of root rot resistance in red raspberry, caused by Phytophtora fragariae var. rubi, was investigated using two experimental breeding designs. Design A was not randomly mated and genetic parameters could not be calculated. Design B was therefore randomly mated to make it possible to do such estimations. Considerable genetic variation was associated with the recorded traits on seedlings tested in a glasshouse. Disease index and % survival were both found to be highly heritable with broad sense heritabilities (H²) close to 0.9 in each design. Estimates of narrow sense heritability (h²), indicated that progress towards resistance would be moderate. In the first design the cultivars Festival, Asker, Boyne and Sentry and the clones N85-02-13 and N85-06-140 had high general combining abilities. Some crosses had a high specific combining ability indicating the presence of non-additive genetic variation.     

Number of crosses and population size for participatory and classical plant breeding

In the breeding of self-pollinating crops, crossing creates variation upon which selection is exerted. If the value of crosses cannot be predicted then this uncertainty means that many crosses need to be made. However, since there is a limit to the capacity of a breeding programme, more numerous crosses result in each cross having a small population size, fewer progenies in later generations and a lower probability of recovering good genotypes from each cross. Published theory on the optimum number of crosses in a plant breeding programme, for a predominantly self-pollinating crop, usually assumes that all crosses are equal value. This overestimates the number of crosses required. When the optimum size of a population in a favourable cross is considered, theory predicts that very large populations are desirable. The required population size is even larger if linkage of loci controlling different traits is also considered. Hence, in an inbreeding crop, one possible strategy is to select a small number of crosses that are considered favourable and produce large populations from them to increase the probability of recovering superior genotypes. In an out breeding crop, the analogy is a few composites with large population sizes. This low-cross-number strategy is ideally suited to the particular constraints and advantages of participatory plant breeding. Such an approach, although not essential, may still be advantageous in classical breeding. When a breeding programme is based on few crosses, which parents are chosen is crucial and farmer participatory methods are highly effective in narrowing the choice. Modified bulk population breeding methods, and recurrent selection are desirable strategies in the participatory plant breeding of self-pollinating crops when combined with a low-cross-number approach. This revised version was published online in August 2006 with corrections to the Cover Date.     

月季遗传多样性和杂交亲本的选择

选取‘月季夫人’、‘希望’、‘加里娃达’、‘金徽章’、‘粉散’、‘杰乔伊’、‘红双喜’、‘唐红’、‘绯扇’、‘月季中心’、‘热带日落’、‘彩云’、‘武士’、‘金凤凰’等月季品种作为研究对象,分别进行表型性状和数量性状的统计与分析。利用NTsys软件进行数据分析获得了各品种间的遗传相似系数和遗传距离,使用SAS8.0统计软件分析材料之间的遗传多样性指数关系,比较14个不同品种的月季种间表型差异和各个表型之间的相关系数。研究结果表明,14个月季品种之间的遗传关系在许多性状上差异显著,遗传相似性系数在0.125~0.438之间,均未超过0.500,是较为理想的杂交亲本候选材料组合。该研究为中国月季资源的多样性评价、遗传多样性、杂交亲本的选择提供了理论依据。     

9个云南甘蔗创新亲本作为父本的经济育种值分析

选用9个含有云南甘蔗野生血缘的创新材料作为父本,与31个国内外不同类型的母本进行杂交,获得38个杂交组合。参照澳大利亚家系试验方法,借助R软件,分析了创新亲本及家系的经济育种值和经济遗传值。结果表明:9个创新亲本中,云瑞04–48和云瑞03–393的经济育种值最高,作为父本应该重点加强利用;云瑞05–171和云瑞05–704可根据育种规模适当使用;38个家系中,MY57–62×云瑞03–393、Lho83–153×云瑞04–48、崖城71–374×云瑞05–171、RB85–5156×云瑞03–393、VMC96–60×云瑞05–704、M336×云瑞03–393等家系的经济遗传值较高,可作为选育优良甘蔗新品种的重点家系,建议降低选择强度,避免优良单株漏选。     

玉米化学诱变材料利用研究 I. F1杂种品质性状的杂种优势表现

以4个常用自交系作母本，5个经过EMS化学诱变处理并经多代自交纯合的材料作父本，按NCII设计配成20个杂交种，研究了其中3个品质性状的杂种优势表现。结果表明：①杂交种在脂肪含量上的平均表现介于雌亲平均数和雄亲平均数之间；在淀粉含量上既低于雌亲平均数又低于雄亲平均数；在蛋白质含量上既高于雌亲平均数又高于雄亲平均数；②离中优势较为普遍，有53.3%的性状-组合存在显著的离中优势，尤其是蛋白质含量，离中优势显著的组合达85%；③有18.3%的性状-组合存在显著的超高亲优势，有11.7%的性状-组合存在显著的超低亲优势；④在蛋白质含量上，材料M04003、M04008、M04010所配制的组合几乎都表现出超亲优势，为较好组合。     

玉米化学诱变材料利用研究I.F_1杂种品质性状的杂种优势表现

以4个常用自交系作母本,5个经过EMS化学诱变处理并经多代自交纯合的材料作父本,按NCII设计配成20个杂交种,研究了其中3个品质性状的杂种优势表现。结果表明:①杂交种在脂肪含量上的平均表现介于雌亲平均数和雄亲平均数之间;在淀粉含量上既低于雌亲平均数又低于雄亲平均数;在蛋白质含量上既高于雌亲平均数又高于雄亲平均数;②离中优势较为普遍,有53.3%的性状-组合存在显著的离中优势,尤其是蛋白质含量,离中优势显著的组合达85%;③有18.3%的性状-组合存在显著的超高亲优势,有11.7%的性状-组合存在显著的超低亲优势;④在蛋白质含量上,材料M04003、M04008、M04010所配制的组合几乎都表现出超亲优势,为较好组合。     

黑穗醋栗优良杂交亲本筛选及组配试验

以“J96-16-5”、“y96-9-4”、“B98-2-4”和“B98-2-7”为试材,“奥依宾”为对照品种,对4个黑穗醋栗优良品系进行综合性状的比较与评价.结果表明:优质丰产性状突出的品系为“J96-16-5”、“Y96-9-4”和“B98-2-4”.选择“J96-16-5”作为母本,“晚丰”、“Y96-9-4”、“奥依宾”、“B98-2-4”作为父本,配置杂交组合,进行杂交试验.4个组合坐果率均正常,获得了较理想的杂交种子数量.     

用于杂交种改良的群体的遗传评价

用于杂交种改良的供体亲本的选择一直是人为的,没有完善的数量遗传理论指导。本文采用数量性状基因分组的概念,依据加性——显性模型,给出了评价群体供体亲本的9个遗传参数,可以有效地指导杂交种改良:①EP_4值较大的群体可作为供体亲本;②若 Cp_2+Dq_s>Cq_2+DP_s,则应用群体 P 改良 I_1,反之,则应用 P 改良 I_2;③可以运用遗传参数进行杂交种改良的育种决策;④显性度大小对于育种决策有重要影响。