Genetic and Agronomic Effects on Milling Qualities of Lentil (Lens culinaris Medik.)

Abstract

Red lentil (Lens culinaris Medikus) is primarily consumed in dehulled form (dhal). Canadian red lentils can be variable for dehulling due to adverse weather conditions at harvest, unique crop management practices, and seed genetics. The research objectives were to investigate the effects of harvest aid herbicides, mid-season applied fungicides, and seed coat color on milling quality, and to identify and map genetic associations with milling characteristics. In field experiments from 2012-2014, potential harvest aid herbicides alone and/or tank mixes with glyphosate, three common fungicides (pyraclostrobin, azoxystrobin, and chlorothalonil), and the four- basic seed coat ground colors of red lentil genotypes were examined for milling quality and milling quality traits were mapped using a recombinant inbred lentil population. Diquat applied alone or in combination with glyphosate as desiccants resulted in increased dehulling efficiency (DE) and milling recovery (MR). Seed glyphosate residue was negatively associated with germination, vigor, DE, and MR, but positively associated with football recovery (FR). Single applications of strobilurin or chlorothalonil did not affect seed yield. Pyraclostrobin application significantly increased DE (+3.5%) in one site year. At a stemphylium blight (SB) affected, significant reductions occurred for seed yield (-46%), DE (-29%), MR (-28%) and FR (-16%). Lentil genotypes expressing the recessive tgc allele (green and gray seed coats) had higher DE and MR than those expressing the Tgc allele (brown or tan seed coat) but had lower FR in two site-years. Genotype, site-year, and their interactions were significant for seed weight, diameter, thickness, and plumpness and for milling quality traits. Broad sense heritability of DE and MR was moderate, and low for FR. Multiple QTLs for milling traits were detected in six of seven linkage groups (LGs). The most stable QTLs associated with DE and MR clustered on LGs 1, 2, 3 and 7. FR QTLs clustered on LGs 4, 5, 6 and 7. Maintaining or improving lentil milling quality can be accomplished by (1) applying diquat alone or in combination with glyphosate, (2) managing SB disease, (3) breeding for uniform seed size with green or gray seed coat color to maximize DE and MR, and with brown seed coat color to maximize FR, and 4) using milling quality markers in genetic improvement. The results of this research could influence future crop management and breeding strategies for minimizing losses in lentil milling.