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以自由授粉群体和品系间杂种为对照,研究了甘蓝型油菜连续自交后代在胚胎发育上表现的效应。自交后代的胚和胚乳发育在授粉5天以后开始落后于杂交组,致使自花授粉的成熟种子较小,且含油率降低。与自由授粉相比,自交组花粉管生长较慢,受精较晚,胚乳游离核数较少,原胚生长缓慢。自交后代中常发生单受精、合子或幼胚退化以及游离核胚乳解体等异常现象,同时在受精频率、游离核数和原胚细胞数方面的变异系数,都较自由授粉组为大,表明至少在胚胎发育前期,连续自交后代甚至比处于杂合状况的自由授粉群体更不整齐一致。讨论了变异发生的原因及预测自交衰退和杂种优势的可能性。
Free pollinating population and cross between lines were used as control to study the effect of continuous selfing progeny of Brassica napus on embryonic development. Embryo and endosperm development of the selfing offspring lagged behind the crosses after 5 days of pollination, resulting in smaller selfed-pollinated seeds with reduced oil content. Compared with free pollination, self-pollinated pollen tube grew slowly, fertilized late, less endosperm free nuclei, embryo growth slow. Inbred offspring often occur single fertilization, zygote or immature embryo degradation and the free endosperm disintegration and other anomalies, while the frequency of fertilization, free nucleation and the number of blast cells in the coefficient of variation were larger than the free pollination group that at least In preimplantation, successive selfed offspring are even more irregular than free pollinators in heterozygous status. Discusses the causes of variation and the possibility of predicting self-fertility and heterosis.