水稻幼穗离体培养植株再生率的遗传分析

GENETICS OF PLANT REGENERATION IN IMMATURE PANICLE CULTURE OF RICE (ORYZA SATIVA L.)

提高植株再生率是体细胞遗传研究的重要课题。本项研究以桂朝,IR36,南京11号,IRGA 409,Tetep,Costa Rica 1119,Cica 6,Cica 8,Lemont及Short Tetep等10个水稻品种为材料,按完全区组设计种植上述品种,并采集适龄幼穗离体培养,比较了植株再生率的品种间差异。结果表明:品种(即遗传型)的平均再生率呈显著差异。作者从上述10个品种中选取了易培养及难培养的四个亲本,配制4×4完全双列杂交,取其F_1,F_2,F_3和回交世代(P_1F_1及P_2F_1)进行幼穗培养。并以世代平均数法(Gamble,1962)进行性状的遗传分析,数据以SAS软件处理、IBM-AT微机统计分析。结果表明:显性基因效应(d)及上位效应(aa,dd)是构成世代平均数变异的主要因素。按亲子回归法计算的遗传力估计值为0.25。作者认为,在进行体细胞无性系变异研究时,应选用易培养的亲本为外植体的供试材料。

The capacity to regenerate sufficient numbers of somaclones to produce adequate population sizes from which to select is an important component of utilizing somaclonal variation for cultivar improvement. This study was conducted to determine the genetics of regeneration ability in immature panicle culture. Rice immature panicles derived from 10 cultivars, 12 F_1 hybrids from a 4×4 diallel, their F_2 and F_3 progenies, and 24 backcross hybrids were cultured in vitro. Significant genotypic differences in regeneration ability were found among the 10 cultivars. The US cultivar Lemont possessed a higher regeneration ability, averaging 8.58 plants per panicle. In contrast,the indica cultivar IR36 had a low regeneration ability, averaging 0.14 plant per panicle. Generation mean analysis of regeneration ability revealed significant values for the estimates of dominance gene effects (d), and for additive × additive (aa) and dominance × dominance (dd) epistatic effects, but showed additive effects to be of minor importance. The heritability estimate calculated by parent-offspring regression was 0.25. Since additive effects are of minor importance and the heritability estimate is low, improving regeneration abilities through hybridization does not appear practical. Conducting an initial screening within possible genotypes to identify those with inherently high regenerative abilities, such as Lemont or IRGA 409, appears to be a better alternative.