Summary Darwin proposed that pollen size should be positively correlated with stigma depth rather than style length among species given that pollen tubes first enter the stigma autotrophically, then grow through the s...Summary Darwin proposed that pollen size should be positively correlated with stigma depth rather than style length among species given that pollen tubes first enter the stigma autotrophically, then grow through the style heterotrophically. However, studies often show a posi-tive relationship between pollen size and style length. Five floral traits were observed to be correlated among 42 bumblebee-pollinated Pedicularis species （Orobancha- ceae） in which stigmas are distinct from styles. The phylogenetic independent contrast analysis revealed that pollen grain volume was more strongly correlated with stigma depth than with style length, consistent with Darwin＇s functional hypothesis between pollen size and stigma depth.展开更多
Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine map- p...Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine map- ped or cloned, the underlying genetic architecture remains unclear. We performed a genome-wide associ- ation study on stigma exsertion and related floral traits using 6.5 million SNPs characterized in 533 diverse accessions of Oryza sativa. We identified 23 genomic loci that are significantly associated with stigma exsertion and related traits, three of which are co-localized with three major grain size genes GS3, GW5, and GW2. Further analyses indicated that these three genes affected the stigma exsertion by controlling the size and shape of the spikelet and stigma. Combinations of GS3 and GW5 largely defined the levels of stigma exsertion and related traits. Selections of these two genes resulted in specific distributions of floral traits among subpopulations of O. sativa. The low stigma exsertion combination gw5GS3 existed in half of the cultivated rice varieties; therefore, introducing the GW5gs3 combination into male sterile lines is of high potential for improving the seed production of hybrid rice.展开更多
基金This work was supported by the Grants from Chinese Ministry of Agriculture (No. 948-2001-101), Chinese Ministry of Science and Technology (No. 2003AA207010), Shanghai Municipal Science and Technology Commission (No. 02ZC14082), and the Rocke-feller Foundation.
基金supported by the National Science Foundation of China (Grants no.31270281, U1402267) to SQH
文摘Summary Darwin proposed that pollen size should be positively correlated with stigma depth rather than style length among species given that pollen tubes first enter the stigma autotrophically, then grow through the style heterotrophically. However, studies often show a posi-tive relationship between pollen size and style length. Five floral traits were observed to be correlated among 42 bumblebee-pollinated Pedicularis species （Orobancha- ceae） in which stigmas are distinct from styles. The phylogenetic independent contrast analysis revealed that pollen grain volume was more strongly correlated with stigma depth than with style length, consistent with Darwin＇s functional hypothesis between pollen size and stigma depth.
文摘Stigma exsertion, a key determinant of the rice mating system, greatly contributes to the application of heterosis in rice. Although a few quantitative trait loci associated with stigma exsertion have been fine map- ped or cloned, the underlying genetic architecture remains unclear. We performed a genome-wide associ- ation study on stigma exsertion and related floral traits using 6.5 million SNPs characterized in 533 diverse accessions of Oryza sativa. We identified 23 genomic loci that are significantly associated with stigma exsertion and related traits, three of which are co-localized with three major grain size genes GS3, GW5, and GW2. Further analyses indicated that these three genes affected the stigma exsertion by controlling the size and shape of the spikelet and stigma. Combinations of GS3 and GW5 largely defined the levels of stigma exsertion and related traits. Selections of these two genes resulted in specific distributions of floral traits among subpopulations of O. sativa. The low stigma exsertion combination gw5GS3 existed in half of the cultivated rice varieties; therefore, introducing the GW5gs3 combination into male sterile lines is of high potential for improving the seed production of hybrid rice.
