Variation in shoot and root characteristics and their association with drought tolerance in lentil landraces

Abstract

Lentil (Lens culinaris Medikus subsp. culinaris), generally grown as a rainfed crop, is often subjected to drought. Drought tolerance is closely related to the distribution of root systems in the soil. We studied seedling shoot and root characters in a set of eight randomly selected lentil genotypes collected from Ethiopia, India, Iran, Syria and ICARDA. Each group of genotypes represents a specific adaptation to the environmental conditions associated with its area of origin. The genotypes were evaluated during two seasons (1997 –1999) under field conditions. Thirty-five-day-old seedlings grown in pots in the open air were assessed for stem length, stem weight, taproot length, lateral root number, total root length and total root weight. Combined analyses over 2 years showed that these characters exhibited significant genotypic variability. Stem length, taproot length and lateral root number were highly correlated, both amongst themselves and with yield. High heritability estimates provided reliability in screening based on these traits. Regression analysis showed that stem length alone accounted for 85% of the variance that occurred in seed yield per plant. Cluster analysis showed that the landraces that originated in Iran and Syria, and the breeding lines developed at ICARDA are distinctly different from the lentil accessions that originated in countries at more southerly latitudes (India and Ethiopia). However, of the total of 40 genotypes, only one line (ILL 6002) was strikingly different from all other test genotypes. This line exhibited significantly superior root and shoot traits and yield, and, therefore, is a valuable germplasm for breeding drought tolerant cultivars.