| As an important component of maize breeding, improving the external morphology of maize plants is not only an important selection of indicator to the plant type breeding but also an effective way to further increase production. Therefore, exploring the inheritance of plant type-related traits that is useful for mapping and analyzing pant-type traits QTL, for promoting the density-based breeding and molecular marker assisted breeding is important theoretical and practical significance. F2:3 families were constructed deriving from the typical compact plant type inbreed line Yu82 and the typical spreading plant type inbreed line Shen137. Genetic studies of characters related to plant type were analyzed under the environments of Zhengzhou and Xingzheng.223 pairs SSR markers were selected to consturct a genetic linkage map, and QTL mapping and analysis was carried out with complex interval mapping. The main results in this study were as follows:1. F value of the traits such as leaf angle, leaf orientation value, leaf length, leaf width, plant height and ear height, internode length above upmost ear in the F2:3 families have significant differences, the frequency of all traits show continuous changes and normally distribution, so the F2:3 population can be used in QTL mapping and analysis.2. the leaf angle and leaf orientation value were showed mid-parent heterosis, the genetic ability were higher, attaining 81.15 and 89.03 respectively; The other traits such as leaf length, leaf width, plant height and ear height were showed evidence excess-parent heterosis, attaining 81.25,78.92,89.03,72.95 respectively; the every internode length above upmost ear were showed evidence excess-parent except the third internode length above upmost ear which was showed mid-parent heterosis, the genetic ability were higher, attaining 83.46,81.32,79.64,82.35,82.14.3. The 222 pairs SSR markers were selected to construct a genetic linkage map of F2:3 with the genetic distance of 2241.8cM (centimorgan) and on an average of 10.1cM using Mapmaker 3.0. And the shortest genetic distance is 0.1 cM.4.41 QTL were detected of 7 traits, distributing on 1,2,3,4,5,7,9 and 10 chromosome respectively, and 9 of which on chromosome 1. In terms of genetic effect, the additive effect play an important role in maize; In terms of action, the partial dominance play an important role and addictive, dominate, overdonminate also play a role.5. The major QTL was detected, such as leaf angle, leaf orientation value, leaf length, leaf width, plant height, ear height and internode length above upmost ear. Furthermore, the distance was close to the marker what were at two sides of the markers. Leaf angle was detected one major QTL in bin 1.02, the nearest markers was umc2226 and contribution rate20.5%. Leaf orientation value was detected one major QTL in bin 1.02, the nearest markers was umc2226 and contribution rate 24.9%. Leaf length was detected one major QTL in bin 7.03, the nearest markers was umc1015 and contribution rate 14.3%. Leaf width was detected one major QTL in bin 3.01/3.02, the nearest markers was umc1325 and contribution rate 22.6%. Plant height was detected one major QTL in bin 7.01, the nearest markers was umc2325 and contribution rate 9.5%. Ear height was detected one major QTL in bin 4.08, the nearest markers was umc1999 and contribution rate 12.1%; qThiIL3, qForIL3, qFifIL3 respectively from the third, the forth and the fifth internode length above upmost ear may be a major QTL which control internode length.There is a common marker interval to qThiIL3, qForIL3 and qFifIL3. Single QTL contribution to phenotypic variation ranged from 8.89% to 16.36%; besides, phenotypic variation of qFirIL1, qSecIL9, qThiIL2 respectively from the first, the second and the third internode length above upmost ear were above 10.3%. Improvement plant type can be used these QTL markers to speed up the breeding process. |
PDF Full Text Request