Molecular characterization of tin-l locus ofF2 NIL population in winter bread wheat

Abstract

The tillering inhibition gene (tin) that reduces tillering in wheat (Triticum aestivum) is also interlinked other yield components. The present research was conducted to study the effect on tinl locus other yield components in bread wheat. Using BCIF2 line Cap_20_1_1 fixed line with 87% Caphom (reculTent parent), reciprocal backcrosses were made with Caphom at Quaid-i-Azam University Islamabad. Phenotypic screening of 800 BC2F2 populations revealed segregation of Tiller number, Plant height, Spike length, Grain per spike, grains per spikelet, TKW and GY. Significant variation was found in tiller number among the population ranging from 1-17 tillers. In BC2F2 population we identified 190 (24%) individuals with less than 4 tillers, whereas, 610 individuals (76%) with more than 5 tillers. Tiller number had significant positive relationship with PH(r=0.32) spikelet per spike(r=0.24) and GY(r= 0.34) .Whereas tiller number had a significant negative correlation with Spike length (r= -0.005) Grain per spikelet (r=-0.30) and thousand kemel weights (r= -0.28).Like tiller number, other agronomic traits are also segregating according to Mendel law of segregation. In order to detennine the molecular basis of tin, we constructed fine map QTL from BCIFI (heterozygous). This fine mapped QTL corresponded to 3.5Mbp region on the physical map and had 12 genes on it. Whereas, a Micro RNA was identified to be overexpressed in the zone by our collaborators in France. To validate F2 mapping population was constructed to create recombination between the two genes