Effects of cytoplasm on heterosis and combining ability for agronomic traits in rice (Oryza sativa L.)

Summary Effect of sterilizing (WA) cytoplasm on heterosis and combining ability for days to flowering, plant height and grain yield in rice was studied in 70 crosses and their reciprocals produced by 10 cytoplasmic male sterile (A), their maintainer (B) and seven restorer (R) lines following line x tester design. The materials consisting of 140 hybrids (70 A/R and their reciprocal 70 R/B) plus 17 parental lines (10 B + 7 R) were evaluated under six environments, created by growing in three fields with different fertilizer doses (0, 60, 120 kg N/ha) and 2 seasons (dry and wet) during 1986 at IRRI farm. Reciprocal cross effect (A/R vs R/B) were highly significant for all the three traits. Interaction of reciprocal cross effects with environments were also highly significant for yield and days to flowering. Cytoplasmic effect for yield, days to flowering and plant height were estimated by comparing A/R and R/B combination and testing the significance of difference with LSD value. In order to avoid confounding effect of spikelet sterility on yields, twenty crosses showing normal spikelet fertility were selected. Both positive and negative cytoplasmic effects were observed for the three traits. The effects were modified by environments, except for plant height. Heterosis for all three traits was also affected by cytoplasm, however, manifestation of cytoplasmic effects was higher for heterosis for days to flower than in heterosis for yield and plant height. Effect of cytoplasm was more pronounced on general combining ability effects of parents than specific combining ability effects of crosses. Among the parents two CMS lines A4 (IR54752A) and A8 (IR22107-113-3-3A) and two R lines: R2 (IR46) and R7 (IR9761-19-1) showed consistent positive effect of cytoplasm on general combining ability. These lines have given several good heterotic combinations. The study indicated the usefulness of evaluating diverse cytoplasmic sources in various nuclear genotypes bred for hybrid rice breeding program.     

Identification of the Putative Cytoplasmic Donor of a CMS System in Brassica juncea

Chloroplast (cp) and mitochondrial (mt) DNA restriction profiles of a cytoplasmic male sterile (CMS) line of Brassica juncea and its maintainer line were compared and found to be markedly different. Comparison of cpDNA restriction profiles of fifty different species of genus Brassica and some allied genera showed that the cpDNA profiles of CMS lines were similar to that of B. tournefortii for twenty different restriction endonucleases. This CMS system is thus not of spontaneous origin as reported earlier, but is alloplasmic in nature. Comparison of restriction profiles of mtDNA of B. tournefortii and CMS lines revealed some differences which might either be due to changes in DNA pattern during the transfer, or, due to the cytoplasm coming from a B. tournefortii line different from the one used in this study.     

Fertility restoration of new CMS sources in sunflower (Helianthus annum L.)

The development of commercial sunflower hybrids based on new CMS sources is of special interest for reducing the potential risk of vulnerability to pathogens and for increasing genetic diversity. From 263 test crosses involving nine new CMS sources, i.e. ANL1, ANL2, MAX1, PEF1, PET2, ANN1, ANN2, ANNS and ANN4, five lines were selected as potential restorers for PEF1, PET2 and ANN4. In test crosses between all nine CMS sources and these five restorer lines evaluated in 2 years, seven fully restored hybrids could be identified. These hybrids, based on ANL1, ANL2, MAX1, PEF1, PET2, and ANN4, showed good agronomic performance for plant height, days to flowering, maturity and oil content. Segregation analyses of the F2 populations indicate that a single dominant restorer gene was sufficient to restore pollen production of hybrids based on ANL2, PEF1 and PET2. For restoration of ANN4, two dominant complementary genes are required. In restoration of fertility in the crosses of ANL1 and MAX1 investigated, two dominant genes are involved each of which on its own allows the production of fertile plants.     

棉花细胞质雄性不育育性恢复基因的定位及分子标记辅助育种研究进展

棉花细胞质雄性不育系统在实现棉花杂交种子大规模生产和培育高产、优质、抗逆等棉花新品种中具有重要的应用价值,而恢复系的好坏对细胞质雄性不育系杂交种的选育的利用起着举足轻重的作用。因此,培育优良恢复系至关重要。主要介绍了棉花细胞质雄性不育系、恢复系的类型,综述了棉花细胞质雄性不育育性恢复基因的遗传方式和遗传定位研究进展,讨论了恢复基因的精细定位和分子标记鉴定在分子标记辅助育种中的意义和应用前景,并针对目前存在的问题提出相应对策。     

三系辣椒新品种沈研18号的选育

沈研18号是以辣椒细胞质雄性不育系A074—3为母本,恢复系0952—7为父本配制的一代杂交种。果实长灯笼形,果纵径15．0cm果横径9．7cm,果色绿,果面略皱,微辣,单果质量195．0g,可食率85％以上。Vc含量61．7mg／kg（鲜质量）,可容性总糖4．08％。适于辽宁、河北、山东、吉林、黑龙江、内蒙古、新疆、...     

辣椒胞质雄性不育（CMS）基因型的鉴定方法

利用材料与不育系测交,F1代不育则材料的基因型为N（msms）;F1代全恢复则材料的基因型为N（MsMs）或S（MsMs）,为进一步判断,分别以其为母本与基因型为N（msms）的材料杂交,F2代分离出不育株的则其基因型为S（MsMs）;F1代一半不育,自交后分离,后代出现1/4不育株则材料的基因型为S（Msms）,否则...     

早熟、优质、抗病甜椒三系杂交种沈研15号的选育

沈研15号是以细胞质雄性不育系A02-7为母本,以恢复系0840-7做父本配制而成的三系甜椒杂交种。该品种早熟,果实方灯笼形,果面光滑,味甜。辽宁省辣椒区域试验平均总产量3710.4kg,平均增产11.0%;国家辣椒区域试验2a平均总产量2753.5kg/667m~2,比对照冀研6号平均增产2.8%。沈研15号适应早春大棚、秋延迟、越冬温室等多种栽培方式。     

甘蓝细胞质雄性不育材料分子鉴定及花器官形态对核背景的响应

对从国内外引进的15份甘蓝细胞质不育材料进行分子鉴定,并通过多代连续回交转育,研究转育后代花器官形态对核背景的响应。结果发现,15份不育材料中有14份为萝卜胞质不育（Ogu CMS）,仅1份为甘蓝型油菜胞质不育（Nap CMS）。细胞质不育材料花器官对核背景的响应,Nap型主要表现3种类型,第1类与原材料相近或呈负响应,第2类表现为正响应,第3类花器官不同部位响应不一,呈现正或负响应;Ogu型主要表现为不变化或较弱的正响应。不同来源胞质材料的花器形态对同一核背景的响应,因自交系不同而异,对于自交系K1、N4,不同来源胞质材料对其响应趋于一致,对自交系37、F1、G7的响应,在不同来源胞质材料间存在差异。     

茎芥菜胞质四倍体白菜雄性不育系花药发育的研究

 以茎芥菜胞质雄性不育系与四倍体白菜杂交获得的同源四倍体白菜异源胞质雄性不育系及其保持系为材料,采用形态学和石蜡切片方法研究其花药解剖结构及发育。结果表明：该雄性不育为结构性雄性不育,其退化或畸形雄蕊分为5种类型：盾状雄蕊、条状雄蕊、片状雄蕊、羽状雄蕊和瓣状雄蕊。该雄性不育系花药发育败育有两个时期,盾状雄蕊花药败育于孢原细胞分化期,雄蕊整个发育时期均处在孢原细胞分化期,无绒毡层与花粉母细胞的分化,不形成药室,属孢子体败育型;其它类型雄蕊,花药败育发生在雄蕊原基分化时期,由于雄蕊原基偏离正常的分化轨道,形成瓣状化雄蕊。