小麦单位面积穗数和粒长主效QTL紧密连锁KASP标记的开发及其效应评价

[目的]小麦单位面积穗数和籽粒粒长是小麦产量相关的重要农艺性状,对其进行遗传改良有利于提高小麦的产量.通过对前期QTL定位鉴定到的提高单位面积穗数的主效QTL位点QSn.sau-2D.2和提高籽粒粒长的主效QTL位点QKl.sau-3D.2开发相应的KASP分子标记,并在川农18和T1208构建的RILs群体中进行验证...

Development and Effect Evaluation of KASP Markers Closely Linked to Major QTLs of Spike Number Per Unit Area and Grain Length in Wheat

【Objective】Spike numbers per unit area (SN) and kernel length (KL) are both important yield-related traits of wheat. Genetic improvement on SN and KL will help increase the yield of wheat. The corresponding KASP molecular markers were developed for the QSn.sau-2D.2 and the QTL Kl.sau-3D.2, which were identified in previous study for increasing SN and KL, respectively. Both KASP markers were verified and evaluated in the RIL population crossed by Chuannong 18 and T1208, which laid a foundation for better utilization of these two QTLs.【Method】The major QTL QSn.sau-2D.2 for SN and the major QTL QKl.sau-3D.2 for KL were previously identified in the RIL population crossed by Chuannong 18 and T1208. The SNP molecular marker sequence of Wheat 55K SNP array within the two QTLs were used to develop and design the KASP molecular markers. The polymorphic KASP markers were screened with wheat parents and then verified in the RIL population. The selected KASP molecular markers were genotyped and used to identify the corresponding phenotypic traits in Chuannong 18×T1208 RILs population. The effects of the two major QTLs on other agronomic traits were analyzed.【Result】KASP-AX-111151907 and KASP-AX-109962767 have polymorphic between the wheat parents. Subsequently, these two KASP markers were verified in the RIL population linkage with QSn.sau-2D.2 and QKl.sau-3D.2, respectively. KASP-AX-111151907 and KASP-AX-10996276 could divide the genotypes into two groups. According to the phenotype, the average selection rate of KASP-AX-111151907 for multi spike lines was 72.58%, the average selection rate of KASP-AX-111151907 for few spike lines was 71.68%, the average selection rate of KASP-AX -10996276 for long kernel lines was 69.86%, and the average selection rate of KASP-AX-10996276 for short kernel lines was 61.52%, indicating the reliability of the two KASP markers. Moreover, the genotyping results based on KASP molecular markers showed that the two QTLs had significant effects on plant height, 1000 kernel weight, kernel length, kernel width, kernel diameter ratio, spike numbers per unit area and kernel weight per spike, respectively. The validation in the RIL population of Chuannong17×Chuannong11 also indicated that these two KASP markers had a certain effect on the selection of the corresponding traits.【Conclusion】This study developed two KASP markers for two major QTLQSn.sau-2D.2 and QKl.sau-3D.2, respectively. Both KASP markers can be used for the selection of corresponding traits. These two QTLs which are tightly linked to these two KASP markers could significantly improve the SN and KL, respectively. In addition, QSn.sau-2D.2had negative effects on plant height, 1000 kernel weight, kernel length, kernel width, kernel diameter ratio and kernel weight per spike. On the other hand,QKl.sau-3D.2 had positive effect on plant height, 1000 kernel weight, kernel width, kernel diameter ratio and kernel weight per spike, but had negative effects on SN. These two QTLs and the developed KASP markers can be used in the future high yield wheat breeding program.