A New Strategy of Rice Breeding in the 21st Century II. Searching a New Pathway of Rice Breeding by Utilization of Double Heterosis of Wide Cross and Polyploidization
A New Strategy of Rice Breeding in the 21st Century II. Searching a New Pathway of Rice Breeding by Utilization of Double Heterosis of Wide Cross and Polyploidization
复制标题
DOI：
--
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
C. De
中科院分区：
文献类型：
--
作者：
C. De
这是有关 21 世纪水稻育种新策略的系列论文中的第二篇。提出了利用宽杂交和多倍体化的水稻育种新途径的策略，即：利用基因组间和多倍体的杂种优势以及一些特殊基因的作用。纵观水稻育种史，他们的研究策略都是基于有性生殖和二倍体，总体上都是利用栽培稻和野生稻的优良基因在同一基因组（AA）中的组合。回顾作物进化的趋势，水稻是二倍体，其基因组、DNA含量和染色体尺寸较小。增加基因组数量，提高倍性水平，利用异源多倍体杂种优势将成为水稻育种的新途径。针对同源四倍体饱满种子率低的关键问题，可采用扩大亲本相对距离、减少多价染色体形成、利用无融合生殖、宽亲和性和Ph基因等遗传原理来提高种子育性。实现该战略分三个步骤。首先，选择水稻亚种籼稻、粳稻和爪哇品种的终端型，涉及美国品种之间相互杂交，诱导亚种间多倍体。其次，诱导O. sativa、O. glaberrima和O. barthii形成种间多倍体。第三，诱导AA基因组的栽培稻和B至J的其他8个基因组中不同基因组的野生稻，形成种间异源多倍体。一些具有宽亲和性、无融合生殖、Ph基因等特殊基因的种质将在杂交中发挥重要作用。广泛的亲和性将有助于克服亚种间F1的雄性不育和雌性流产。无融合生殖的特点，无需减数分裂和受精，有利于避免因染色体配对而导致后代分离。而小麦中的Ph基因具有部分同源染色体配对的印象，可用于阻止异源多倍体基因组间部分同源染色体的配对和多价、染色体桥、滞后染色体的形成。这将保证其后代在选择异源多倍体水稻和无融合生殖水稻时具有较高的结实率和良好的利用稳定性。该实验的最新进展提供了良好的结果。以无融合生殖系为亲本，与籼稻、粳稻杂交以及亚洲品种和美洲品种之间的杂交，获得了杂种优势强、结实率高达85%的优良多倍体植株系。这为新育种战略的实现提供了很好的背景。
This is the second one of a series of papers about the new strategies of rice breeding in the 21st century. It is suggested that the tactics of new pathway of rice breeding by utilization of wide cross and polyploidization, i. e using heterosis of intergenomes and polyploid and the role of some special genes. Making a general survey of the history of rice breeding, their research strategies were based on sexual reproduction and diploid, in general, all used the combination of superior genes of cultivated and wild rice in the same genome (AA). Reviewing on the tendance of crop evolution, rice is a diploid with smaller genome, DNA content and chromosome size. Increasing the number of its genomes, getting up its ploidy level, using heterosis of allopolyploid will be a new pathway of rice breeding. To counter the key problem of low percentage of filled seeds in autotetraploid , such measures can be used to raise seed fertility by genetic principle, as enlarging their relative distance of parentages, reducing the formation of polyvalent chromosome and utilizing apomixis, wide compatibility and Ph genes. There are three steps to realize the strategy. First, selecting terminal type of Orysa sativa ssp indica, japonica and javanica involved American cultivars cross each other to induce intersubspecific polyploid. Second, inducing O. sativa, O. glaberrima and O. barthii to form interspecific polyploid. Third, inducing cultivated rice with AA genome and wild rice with different genomes in other 8 genomes from B to J to form interspecific allopolyploid. Some germplasms with special genes such as wide compatibility, apomixis and Ph genes will be taken part of important role in the cross. Wide compatibility will be useful to overcome male sterility and female abortion of F1 of intersubspecies. The characteristic of apomixis without meiosis and fertilization will be helpful to avoid segregation of progeny because of chromosome pairing. And Ph gene as in wheat with impression of the pairing o f partial homologeous chromosomes, can be used to prevent the pairing of partial homologeous chromosomes in intergenomes of allopolyploid and formation of multivalent, chromosomal bridge, lag chromosome. These will ensure for their progenies with high rate of seed set and good stability in utilization of selecting allopolyploid rice and apomictic rice. Recent progress in this experiment have provided a good results. Using apomictic lines as a parent to cross with O. satva ssp indica and japonica and cross between O. sativa ssp Asian and American cultivars had obtained some superier polyploid plant lines with powerful heterosis and high up to 85 % seed set. It has provided a very good background to realize the new breeding strategy.