Genetic Analysis And Molecular Mapping Of A Dominant Heading Period Gene Hd(t)

Rice(Oryza sativa L.ssp.indica)is an important cereal crop and the model species of monocots.Heading period is one of the important agronomic traits of rice.The heading period of rice cultivar affects its cultivation areas and seasonal adoptability,It has been received the extensive attention of breeders for so long.Therefore,detailed understanding of heading period's genetic law is significant for rice breeding practice,Carried on the fine localization and the clone to the related gene,the discussion improves the paddy rice through the molecular level's operation the period of duration character to have the broad application prospect.At the same time,the paddy rice's heading period gene equates in the double seed leaf plant's florescence gene,The regulative adult plant from the vegetative growth the transformation which grows to the reproduction,was also the developmental biology research hot spot in recent years.In crossbreeding process,a restoring line N91 with late heading period was found from the offspring of a cross(Jinhui 10/R21),and N91 was crossed and backcrossed with Jin 23A,which was sterile line with early heading period.The genetic analysis demonstrated the heading period was controlled by a major gene,which tentatively named as Hd(t),This research has carried on the genetic analysis and the molecular mark localization research of the related the gene.The main result is as follows:1.genetic analysis of the Hd(t)A restoring line N91 with late heading period was found from the offspring of a cross (Jinhui 10/R21),and N91 was crossed and backcrossed with Jin 23A,which was sterile line with early heading period.Simultaneously sow the seeds of the parent,F1,F2 and the BC1F1 community.Extracts take the 1/3 of each of the first head counts as the heading,the parent,F1,F2 and the backcross community were carried on the record.The number of days from sow seeds to the heading date is taken as the heading period.The N91 heading period is 108～114 d,The Jin 23A heading period is 90～94 d,The F1 heading period is 96～106 d,the frequency distribution of heading period showed double peaks in F2 and BC₁F₁ population, they are 88～116 d and 84～116 d.The heading period of F1 is situated between the parents, but closer N91,indicates that the late heading of the N91 is equal to the early heading of the Jin 23A is an incomplete dominance.The frequency distribution of heading period showed double peaks in F2 and BC₁F₁ population,take 96 d as the dividing line,the F2 community late heading plant and the early heading plant's separation proportion tallies 3:1,and the BC₁F₁ community late heading plant and the early heading plant's separation proportion tallies 1:1,indicates the late heading character of N91 is controlled by a pair of a major gene.The early heading is quite centralized in the backcross community,and the late heading community is quite scattered,might be controled by a major gene and several minor genes.2.Molecular mapping,of the Hd(t)geneIn the F2 community,chooses 10 early heading single construction to be early heading bulk,10 late heading single construction to be late heading bulk,by using 400 pair of SSR primers to carry on screening to the gene pools.As a result,the RM3555 and RM1364 showed polymorphism between late and early gene pools.SSR patterns amplified with RM3555 and RM1364 in individuals of F₂ segregation population for verification.Linkage analysis demonstrated the Hd(t)linked with two SSR loci RM1364 and RM3555 on the distal end of long arm of chromosome 7.Because F2 community quantity are few,so using SSR patterns amplified with RM3555 and RM1364 in individuals of BC₁F₁ segregation population for verification,the result that the Hd(t)linked with two SSR loci RM1364 and RM3555. Because in BC₁F₁ is late heading single to be more scattered,is inferior model to the early heading,therefore,only selected the early heading to take the localization community. Linkage analysis demonstrated the Hd(t)were 32.7 and 22.5 cM from loci RM1364 and RM3555 respectively,and two SSR loci located at the same side of the Hd(t).According to physical map analysis,the goal gene located between RM3555 and the distal end of long arm of chromosome 7.To locate the Hd(t)in a smaller scope,based on the targeted interval,8 pairs of primers were selected between RM3555 and the distal end of long arm of chromosome 7,Obtained the polymorphism primer of the RM22143,SSR patterns amplified with RM22143,in individuals of the BC₁F₁ segregation population for verification,the result that the Hd(t) linked with RM22143,through linkage analysis,RM22143 was added into the interval of the RM3555 and Hd(t)on the distal end of long arm of chromosome 7,and Hd(t)was 12.9 cM from RM22143.The present result establishes a basic for fine mapping,molecular marker assisted breeding and gene cloning of the Hd(t).