Studies On The Heredity And QTL Of Photoperiod Sensitivity And The Relvant Traits In Maize

Although the tropical and subtropical zone had different germ plasm with our country's and American's in maize, photoperiod sensitivity had restricted its use in temperate zone. Mapping genes related with photoperiod sensitivity by molecular marker not only had important meaning for improving level of using of our country's germ plasm from strategy, but also had important scientific meaning for knowing the heredity of photoperiod sensitive in maize. A genetic linkage group that contained 98 SSR markers was constructed by using the F_2:3 families derived from the typical photoperiod sensitive inbreed CML288 and the typical photoperiod non-sensitive inbreed line Huangzao4. QTL analysis on photoperiod sensitivity and the traits related with photoperiod sensitivity was carried out with complex interval mapping. We, for the first time, put forward that photoperiod sensitivity was measured by relative flowering time (RD). Heredity and QTLs of photoperiod sensitivity and the traits relevant to photoperiod sensitivity were carried out under four environments including summer and spring of temperate and subtropical zone. The results were as follows:1 . The genetic linkage group containing 98 SSR marker was found by using the 258 F_2:3 families derived from CML288 × Huangzao4.This genetic linkage group covered 1,843.5 cM of the whole genome of corn, and the number of marker on each chromosome varied from 5 to 15, and average distance of whole genome was 18.81 cM. The results indicated that the group was suitable for QTLs elementary location.2 .The traits related with photoperiod sensitive including Days-to-Tassel, Days-to- Pollen, Days-to-Silk, plant height and ear height were investigated under four environments. Relative flowering time (RD) in Zhengzhou and Zhoukou were calculated and taken as the index of photoperiod sensitive. The absolute value of thedegree of the skewness of the traits were all smaller than 1 except for Days-to-Tassel in Sanya and the ear height in Zhoukou, the results showed that these traits complied with normal distribution basically, and QTL analysis could be carried out on these traits.3. The hereditary character of photoperiod sensitive of flowering time was different in spring and summer in temperate zone. In spring the sensitive sense was dominance opposed to the blunt sense, and hereditary feature was partial dominances. In summer the sensitive sense was dominance for the blunt sense, and the RD value of Fi has exceeded that of the sensitive inbreed, and hereditary feature was over dominances. The RD value in summer was smaller than in spring.In spring 8 QTLs were found, in which 5 QTLs controlled Days-to-Tassel, and 2 QTLs controlled Days-to-Pollen, and 1 QTL controlled Days-to-Silk, these QTLs were on chromosome 1, 4, 6, 8, 9 and 10 chromosomes respectively. The role way of major QTL controlling 3 photoperiod sensitive indexes were all additive, its contribution rate were 24.97%, 24.37% and 29.98% respectively, the additive effect direction of these QTLs were identical. In summer 5 QTLs were found, in which 3 QTLs controlled Days-to-Tassel, and 1 QTL controlled Days-to-Pollen, and 1 QTL controlled Days-to-Silk, these QTLs were on chromosome 3 and 10 respectively. The role way of major QTL controlling Days-to-Tassel photoperiod sensitive indexes were partial dominances along with over dominance, and single QTL contribution of rate ranged from 5.53% to 15.52%. 1 QTL controlling Days-to-Pollen was detected, it was on chromosome 10, the role way of QTL controlling Days-to-Pollen photoperiod sensitive indexes was additive. Days-to-Silk photoperiod sensitive indexes were so.4. In spring in Zhengzhou 18 QTLs were detected, in which 11 QTLs controlled flowering time, and 7 QTLs controlled plant morphlogy. QTLs controlled flowering time were on chromosome 2> 3, 5. 9 and 10, and there were 2 QTLs on chromosome 2, 3 QTLs on chromosome 3, 2 QTLs on chromosome 5, 1 QTL on chromosome 9, and 3 QTLs on chromosome 10 respectively, the biggest single contribution rate reached 43.75%, and the rest ranged from 4.80% to 14.03% , the role way were additive, partial dominance and over dominance. Allele genes mostly derived from the same parent, as a result, reduced gene effect. QTLs controlling plant morphlogy were on chromosome 3n 4> 5> 7 and 10, there were 2 QTLs on chromosome 5 and 10, and there was 1 QTL on chromosome 3^ 4 and 7 respectively, single contribution rate ranges from 5.35% to 17.37% , the role way was additive and...