Genetic Analysis and Molecular Markers of Root Morphology of Canola.

Abstract

Rapeseed/canola (Brassica napus L.) has both winter and spring form available. Scarce information on genetic control of root system in B. napus is available. The winter type has a vigorous root system whereas the spring type has a weakly developed root system. Three separate studies were conducted on 1,058 F₂ plants to investigate the number of genes controlling the root vigor trait. Crosses and reciprocal crosses were made between spring type parent Regent and winter type parent ARC97018, spring parent Regent and winter parent Lagoda, and spring type parent Legend and winter type parent Lorenz. The F₁ and F´₁ of spring and winter types crosses showed a vigorous root system, indicating the dominant nature of vigorous root system in B. napus. Independent analysis as well as combine analysis of all F₂ plants of the three crosses strongly indicated that three genes are responsible for vigorous root system in B. napus. Root length showed a positive significant correlation with both seed yield per plant and late flowering. SNPs were obtained from genotyping by sequencing data from 90 F₂ plants derived from Regent x Lagoda crosses. A linkage map was constructed with 262 SNP and 3 SSR markers assigned onto 26 linkage groups those cover a total of 2469 cM. The lengths of independent linkage groups were between 9.6 cM to 266.8 cM. Two QTL for root vigor were identified. One of the root vigor QTL was assigned on B. rapa chromosome A03 and B. oleracea C09, and two putative candidate genes, Anthranilate Synthase Alpha Subunit 1 (ASA1) and Reduced Lateral root Formation (RLF) were identified. The SNPs in the respective QTL will be screened against root vigor for other population to develop tightly linked marker for marker assisted breeding program.