Identification of QTL associated with tassel branch number and total tassel length in maize

Abstract

On the basis of 103 SSR linkage map, QTLs associated with tassel branch number (TBN) and total tassel length (TTL) were studied by composite interval mapping with F3 families, which were developed from the cross N87-1 x 9526 and surveyed for phenotype under normal condition (CK) and drought-stress environment (DS). Four QTLs on chromosomes 2, 5, 7, and 10, respectively, were associated with TBN under DS, two of which were not only repeatedly detected on chromosomes 5 and 7 under the CK but also were linked to some QTLs related to drought tolerance that had already been reported in the same mapping population. The two QTLs controlling TTL were identified on chromosomes 2 and 6 under CK, while three QTLs for TTL were detected on chromosomes 2, 4, and 10 under DS. The QTL on chromosome 2 for TTL was consistent under two environments. Most of QTLs for TBN were partial additive while QTLs for TTL were dominant and over-dominant in terms of gene action.