Genovariation And Epistatic Interaction Of Genes For Heading Date In Rice

Heading date is an important agronomic trait in rice (Oryza sativa L), whichalmost totally determines the rice production ares and growth seasons. Single segmentsubstitutions (Single segment substitution lines, SSSL) are ideal materials to analysizegenovariations and epistasis. Analysizing the allelic variations of rice heading dategenes and using pyramiding single segment substitution lines which include riceheading date QTLs (Quantitative trait locus, QTL) to research the genovariation andepistatic interaction of genes for heading date in rice is very important in photoperiodiccontrol of flowering and breeding.Our experiment contains two espects, ten heading date genes were analyzed byusing single segment substitutions, heading date QTLs were investigated by usingepistasis. The main results as follows:1. We use7SSSLs and Huajingxian74(Huajingxian74, HJX74) as experimentalmaterials. According to their field heading date to research10heading date genes.They located3different chromosomes. The third chromosome including four genes(DTH3, OsDof12, Ehd4, Hd16) for heading date were analyzed using forwardgenetics approach. The sixth chromosome including three genes (Hd17, Hd3, RFT1)for heading date were analyzed using forward genetics approach and the tenthchromosome including two genes (Ehd1, Ehd2) for heading date were analyzed usingforward genetics approach. Two different SSSLs (WY17and WY24) and the recipient(Huajingxian74), which contain DTH3were used to analyze allelic variations. Threedifferent SSSLs (WY17, WY24and WY35) and the recipient (Huajingxian74),which contain OsDof12were used to analyze allelic variations. Two different SSSLs(WY17and WY24) and the recipient (Huajingxian74), which contain Ehd4wereused to analyze allelic variations. The SSSL of WY34and the recipient (Huajingxian 74), which contain Hd16were used to analyze allelic variations. The SSSL of WY30and the recipient (Huajingxian74), which contain Hd17, Hd3a and RFT1were usedto analyze allelic variations.The SSSL of WY61and the recipient (Huajingxian74),which contain Hd1were used to analyze allelic variations. The SSSL of WY65andthe recipient (Huajingxian74), which contain Ehd1and Ehd2were used to analyzeallelic variations.In this experiment, we analyzed the difference of rice heading date genes inmany aspects between single segment substitution lines and Huajingxian74to provewhether the difference of these genes result to the difference of heading date. Themethods include CDS sequence alignment, amino acids sequence alignment, aminoacids physical and chemical properties, hydrophobic of amino acids and proteinsecondary structure prediction.2. In the present study, we choose15double segment pyramiding lines bymarker-assisted selections (Marker-assisted selection, MAS), developed from30single segment substitution lines with the same genetic background Huajingxian74, toanalysize the interactions of QTLs. On SY4(WY6/WY9), qHD8-1fromW06-15-18-3-11was epistatic to qHD3-1from W22-03-10-9-11(t); On SY16(WY11/WY17), qHD3-2from W05-1-11-02-07-6was epistatic to qHD8-2fromW5-36-61-9-4-13-8; On SY27(WY17/WY18), qHD3-2from W05-1-11-02-07-6wasepistatic to qHD8-4from W06-15-18-3-11; On SY51(WY16/WY24), qHD3-3fromW08-16-3-2was epistatic to qHD8-3from W02-15-7-3; On SY53(WY18/WY24),qHD3-3from W08-16-3-2was epistatic to qHD8-4from W06-15-18-3-11; On SY62(WY24/WY33), qHD1-1from W18-18-08-05-07was epistatic to qHD3-3fromW08-16-3-2; On SY69(WY24/WY34), qHD3-4from W22-03-10-9-11was epistaticto qHD3-3from W08-16-3-2; On SY70(WY24/WY65), qHD3-3from W08-16-3-2was epistatic to qHD10-1from W22-9-5-2-4-9-3; On SY83(WY16/WY32),qHD11-1from W13-30-49-02-11-8was epistatic to qHD8-3from W02-15-7-3; OnSY92(WY6/WY33), we can not get the conclusion; On SY97(WY24/WY33),qHD1-1from W18-18-08-05-07was epistatic to qHD3-3from W08-16-3-2; OnSY106(WY34/WY60), qHD3-4from W22-03-10-9-11was epistatic to qHD8-5from W15-3-1-38; On SY108(WY32/WY35), qHD11-1from W13-30-49-02-11-8wasepistatic to qHD3-5from W23-03-08-9-1; On SY118(WY35/WY61), two QTLshave additive effects; On SY137(WY18/WY75), qHD3-6from W23-03-08-9-1wasepistatic to qHD8-4from W06-15-18-3-11.In conclusion, the analysis of genovariation and epistasis by using singlesegment substitution lines is the basis of take advantage of rice heading date, it ismeaningful.