Mapping QTLs for Plant Height Variation in Ril Population Derived from Cross Between Harry x Wesley Semi-Dwarf Wheat Lines.

Modification of plant height through introduction of semi-dwarf (Rht) genes in wheat was a key factor in the green revolution. Plant height variation in progenies derived from semi-dwarf wheat lines is very interesting and moves attention to investigate the height variation in progenies derived from semi-dwarf wheat genotypes. In this study a set of 204 RILs derived from crossing ‘Harry’ x ‘Wesley’ semi-dwarf wheat lines containing Rht-B1b gene were used to study and map QTLs responsible for plant height variation  in semi-dwarf wheat populations. Results revealed significant differences among genotypes, environments and genotype x environment interactions.  Heritability of plant height was high (86.6%) and transgressive segregrants were obtained.  A total of 8 QTLs were detected across the five environments on chromosomes 1AL, 3B, 5BL and 7A. QTL Qph.hw.5BL.1 expressed in 3 (High rainfall) and QTL Qph.hw.3B.1 in 2 (Low rainfall) environments.  The phenotypic variance explained by identified QTLs ranged from 5.76 to 12.89%.  Further, 10 pairs of significant digenetic interactions were identified and interactions across chromosomes occurred mostly in the A and B genome. QTL x environment interactions was significant and phenotypic variance explained by QTL x environment interactions ranged from 2.76 to 0.02%. The present study provides new insights to tailor semi-dwarf plant height. Taller semi-dwarfs under drought and shorter semi-dwarfs under irrigation is desirable.