通过异倍性水稻间杂交获得同源三倍体植株

Autotriploid Plants Obtained from Heteroploid Rice Crosses 

以３个二倍体水稻（ＯｒｙｚａｓａｔｉｖａＬ．）（２ｎ＝２ｘ＝２４）和３个同源四倍体水稻（２ｎ＝４ｘ＝４８）为杂交亲本配制６个自交组合和３０个杂交组合。试验结果表明，同源四倍体组合的结实率比较低（１０．０１％～２１．７８％），这可能与其花药内所包含的正常花粉粒比例小而异常花粉粒比例大有关。异倍性杂交组合的结实率更低（０．２０％～１．６４％），但在两种配组方式之间却存在着明显差异，即以同源四倍体水稻为杂交母本而以二倍体水稻为杂交父本则其异交结实率比较高（０．４２％～１．６４％），反之，以二倍体水稻为杂交母本而以同源四倍体水稻为杂交父本则其异交结实率比较低（０．２０％～０．８５％）。在杂交时重复一次授粉能显著地增加多倍体组合的异交结实种子数。除此之外，对ＡＰⅣ（４）×ＡＰⅣ（２）杂交组合的胚胎学观察结果表明，其受精率比较低（３４．２％），其中包括卵细胞的单受精（２５．０％）、中央细胞的单受精（３．３％）以及卵细胞和中央细胞的双受精（５．９％）。通过常规杂交法所获得的同源三倍体成活植株的频率很低（０．０７％），而通过采用杂种子房培养法所获得的同源三倍体植株的成活率比较高（０．７８％），后者的效率比前者要高出１１．１?

The crossability of 30 hybridized and 6 selfcrossed combinations from the reciprocal crossing of 3 diploid rice (Oryza sativa L.) (2n=2x=24) and 3 autotetraploid rice (2n=4x=48) was investigated. The lower seed sets (10.01%～21.78%) of the autotetraploidy combinations may be attributed to the presence of more abnormal pollen in the anthers. The seed sets of the heteroploidy cross combinations were even lower (0.20% ～1.64%), but there was obvious different seed settings between the two mating methods. If the autotetraploid rice was used as the female parents and the diploids as the male parents, higher seed sets (0.42% ～1.64%) were found in the hybridized combination. However,the seed sets in the combinations were lower (0.20% ～0.85%) if the diploid rice was used as the female parents and the autotetraploids used as the male parents. The seed sets of the autoheteroploidy combinations could be outstandingly improved by repeating the pollination twice. Besides, the results from the embryological examination of APⅣ (4) ×APⅣ (2) cross showed that the total rate of fertilizations, including single fertilizations of an egg with a sperm (25.0%), two polar nuclei with a sperm (3.3%), and double fertilization of an egg and two polar nuclei with two sperms (5.9%), was lower(34.2%).The survival rate of the autotriploid plants obtained by the conventional cross method was very low ( 0.07% ), but that obtained by ovary culture method was higher (0.78%). Which surpassed 11.14 times than that of the former.