杂交粳稻F_2代一粒双苗的倍性鉴定

Ploidy identification of two-seedlings per seed in F_2 generation of japonica hybrid rice(Oryza sativa L.)

从杂交粳稻3优18等8个组合的F2代中筛选一粒双苗,并对存活的双苗进行根尖染色体数目和花粉育性的观察鉴定。结果表明:在127 610粒3优18 F2种子中筛选到双苗16株,双苗率为0.012 5%。获得的一粒双苗分为Z-A型和Z-a型两类,每苗都有独立的根系。Z-A型双苗中,Z苗和A苗的根尖染色体数目都是24;Z-a型双苗中,Z苗的根尖染色体数目是24,a苗的根尖染色体数目为12。Z-A型双苗中,Z苗和A苗植株的花药内充满了花粉粒,Z苗植株花粉完全可育,结实正常,A苗植株花粉50%可育,50%不育,与F1相同,结实正常;Z-a型双苗中,Z苗植株花药花粉和Z-A型的Z苗一样,a苗植株花药瘦小,没有花粉粒,自交不结实。

Two-seedlings per seed were screened from F2 generation of 8 combinations, mainly 3 You18, and root tip chromosome number and pollen fertility were observed using the two-seedlings obtained, in japonica hybrid rice. The results indicated that in 127 610 grains of F2 seed of 3 You18, sixteen grains showed two-seedlings per seed （TSPS）, frequency of TSPS being 0. 012 5%. The TSPS obtained were divided into 2 types, Z-A and Z-a. Each seedling of TSPS had independent root system. In Z- A type, chromosome number of root tip from both Z seeding and A seeding was 24, while in Z-a type, chromosome number of root tip from Z seeding was 24, and chromosome number of root tip from ＂a＂ seeding was 12. Anthers from Z plant and A plant in Z- A type were filled with pollens. In Z plant, pollens were 100% fertile and seed setting was normal, in A plant, 50% pollens were fertile, another 50% pollens were sterile but seed setting was normal, the same as FI plants. In Z-a type, anthers and pollens from Z plant were the same as Z plant in Z-A type, anthers from ＂a＂ plant were smaller and thinner than those from Z plant, and had no pollen, no seed was set by selfing.