QTL Analysis Of Maize Shade Tolerant

Maize is an important food, feed and industrial crops, as China's second largest food crops, perennial planting around an area of about 4 million mu, the total output of about 150 million tons, in the national economy occupies an important position.The stress of rain and poor light during the maize growing is often encountered in non-biological adversity,is also the important issue of maize production of the Huang-Huai-Hai area in today's facing. Each year due to stress caused by low light, corn production is lowed by 10 -15%, in serious cases up to 20% -30%. Low-light stress has become a sustainable development of China's maize production of the major constraints. Breeding excellent tolerant maize hybrids of maize genetics and breeding is one of the important goals. Tolerant corn is controlled by multiple genes of quantitative traits using traditional breeding methods to improve their tolerant and less efficient. In this study, inbred lines of strong tolerant of the中72 and inbred lines of weak tolerant of the 502 were for experimental materials,and the F2 mapping groups were prepared.In low-light stress and non-stress conditions, in Zhengzhou and xunxian ,investigate the F3 families tolerant field-related phenotypic traits, the number of days to heading, silking days, male and female interval, specific leaf weight, stem diameter, plant height, ear height. Tolerant QTL associated to the location and genetic analysis are aslo done. Tolerant maize QTL consistency and interoper ability between the effect against tolerant are discussed in the genetic background of different groups of mapping QTL positioning . The main trial findings were as follows:1 716 pairs of SSR primers for maize inbred lines in 72×502 were for the parental polymorphism screening, a total of 210 pairs of polymorphisms were selected primers, and the tags deviated seriously were removed.Using mapping software Mapmaker3.0 , genetic linkage map of maize was obtained with 197 polymorphism, the total length of map 2693.6CM, the average genome-wide map 13.67 cM, a minimum map distance 0.5 cM.2 At xunxian and Zhengzhou the two pilot sites, F2:3 families tasselling days, silking days, ASI, specific leaf weight, stem diameter, plant height, ear height ,which are shade-sensitive traits related , showed genetic characteristics of quantitative traits.F2:3 family close to the average of the parents,and there are a certain number of two-line super-in-laws.3 F2:3 families in shade conditions, tasselling stage and silking period were prolonged, male and female gap intervals were extended, specific leaf weight was lowed, plant height and ear height were decreased ,variability were expanded .The various characters of the whole group are state distribution, so that, F2: 3 family groups can be used for QTL analysis.4 The characters of the F2: 3 families ,in xunxian and Zhengzhou ,under the shade conditions had been QTLs positioned. The number of days tasselling: in Zhengzhou ,a QTL was detected, in xunxian five QTL were detected. A common QTL was detected in Zhengzhou and xunxian, which was located on chromosome 1 , between umc1395-umc2083 and the contribution rates were 12.71%, 6.76%; silking days: four QTL were detected in Zhengzhou point, three QTL were detected in xunxian point.A common QTL was detected in Zhengzhou and xunxian, which was located on chromosome 1 , between umc1403 and phi001, and the contribution rates were 10.93%, 9.85%; ASI: four QTL were detected in Zhengzhou points, two QTL were detected in xunxian point. A common QTL was detected in Zhengzhou and xunxian, which was located on chromosome 1, and the contribution rate of 10.12 percent and 10.01 percent, between umc1403 and phi001.Specific leaf weight: four QTL were detected in Zhengzhou point, two QTL were detected in xunxian point; diameter: no QTL was detected in Zhengzhou, 4 QTL were detected in xunxian point; height: 4 QTL were detected in Zhengzhou, four QTL were detected in xunxian points, three common QTL were detected in Zhengzhou and xunxian, which were located on chromosome 1,4,10, and were located in between umc1082 and bnlg1671, bnlg2244 and umc1051, umc1432 and umc1962 tags, and the contribution rate to 8.45 percent, 8.53%, 7.28%, 9.92%, 10.13%, 8.77%. Ear height: three QTL were detected in Zhengzhou points, five QTL were detected in xunxian points, three common QTL were detected in Zhengzhou and xunxian, which were located on chromosomes 1,4,5, and were located in umc1082-bnlg1671,bnlg2244-umc1051, umc2036-bnlg1879 tags,and the contribution rate of 12.93 percent, respectively, 13.79%, 8.45%, 7.13%, 8.17%, 6.36%.5 The characters of the F2: 3 families ,in xunxian and Zhengzhou ,under the light conditions had been QTLs positioned. The number of days tasselling: three QTL were detected in Zhengzhou points, four QTL were detected in xunxian, a common QTL was detected in Zhengzhou and xunxian, which was located on the first chromosome,between umc2083-bnlg1057 ,and the contribution rate of 10.25% , 14.39%. Silking days: three QTL were detectedin Zhengzhou points, two QTL were detected in xunxian points, a common QTL was detected in Zhengzhou and xunxian, which was located on the first chromosome, between markers umc2083-bnlg1057,and contribution rates were 10.95%, 10.23%.The number of days between the male and female: five QTL were detected in Zhengzhou points, six QTL were detected in xunxian point, two common QTL were detected in Zhengzhou and xunxian, which were located on chromosome 1and 8 ,between umc1976-umc1403, umc1960-mmc0181 ,and respectively the contribution rate of 10.23%, 6.88%, 4.66%, 7.02%. Specific leaf weight: four QTL were detected in Zhengzhou points, three QTL were detected in xunxian points, a common QTL was detected in Zhengzhou and xunxian, which was located on chromosome 10 between marker bnlg594-bnlg2190 ,and respectively the contribution rate of 6.75%, 5.14%. Diameter: two QTL were detected in Zhengzhou points, two QTL were detected in xunxian, no common QTL was detected. Height: four QTLwere detected in Zhengzhou points, five QTL were detected in xunxian points, two common QTL were detected in Zhengzhou and xunxian, which were located on chromosome 4,8, in bnlg2244 and umc1051, umc1202 and umc1562 ,and respectively the contribution rate of 11.81%, 13.35%, 8.2%, 6.72%. Ear height: five QTL were detected in Zhengzhou points, which are located on chromosome 1,3,4,5,7, the contribution rate ranged from 4.23% -9.86%, the cumulative contribution rate of 33.98%; 2 QTL were detected in xunxian, which were located on chromosome 1,5, respectively the contribution rate of 4.97%, 6.6%, the cumulative contribution rate of 11.57%, no common QTL had been detected .