穗粒数基因Gn1a在直立穗粳稻品种中的遗传效应分析

Genetic effects of Gn1a controlling grain number in the erect-panicle type Japonica rice

Gn1a是控制穗粒数的重要基因,对提高水稻单产具有重要意义。利用Gn1a基因内功能标记Gn1a-M1对44份迟熟中粳品种进行检测,结果显示该基因尚未在直立穗迟熟中粳品种中得到应用。为探明Gn1a在直立穗粳稻中的遗传效应,构建一套以直立穗粳稻品种海丰1号(gn1agn1a)为受体亲本,籼稻黄华占(Gn1aGn1a)为供体亲本,包含133个系的导入系群体,并通过重测序明确其中39个导入系携带Gn1a基因。在此基础上,通过对10个携带Gn1a基因导入系、10个未携带Gn1a基因导入系以及受体亲本农艺、产量和品质性状的测定及分析,明确了Gn1a基因在直立穗粳稻背景下能显著增加二次枝梗数、二次枝梗颖花数、穗长及一次枝梗数,但显著降低单株穗数;在外观品质上表现为粒宽显著增加、长宽比显著减小,垩白粒率和垩白度有增加的趋势,但对稻米淀粉理化性质和蒸煮食味品质影响较小。

The application of Gn1a, a major gene, in increasing grain number per panicle, is of great significance to improve the yield of rice. In this study, Gn1a-M1, a functional marker designed for detecting the allele of Gn1a, was used to screen 44 late-maturity medium Japonica varieties, revealing that Gn1a has not yet been used for breeding late-maturity medium Japonica varieties with erect panicle. Then, a set of 133 introgression lines were constructed, utilizing Haifeng1(gn1agn1a) as receptor and Huanghuazhan(Gn1aGn1a) as donor, and 39 introgression lines carrying Gn1a were identified by re-sequencing. Further, the agronomic traits, yield-related and quality-related traits of 10 introgression lines carrying Gn1a, 10 introgression lines carrying gn1a and Haifeng1, were observed. The secondary branch number, secondary spikelet number, panicle length, primary branch number and grain width were found to increase significantly, but the number of panicles per plant and length-width ratio decreased significantly while using Gn1a in erect-panicle Japonica varieties.With grain width increased,the introgression lines carrying Gn1a preferred to show high chalky rice rate and chalkiness degree,indicating Gn1athat plays a role in the appearance quality of erect-panicle Japonica varieties.Else,Gn1a was found to merely have minor effects on the physi-chemical properties and cooking and eating quality of erect-panicle Japonicavarieties.