Breeding potential of durum wheat landraces from Jordan I. Phenotypic diversity

Abstract

A Jordanian durum wheat collection consisting of 132 landraces was evaluated in an arid and a semiarid location for 21 morphological and developmental traits. Phenotypic diversity indices (H) were calculated for traits, districts, and regions of collection. Average diversity for Jordan was 0.675 ± 0.05. The pattern of variation of individual traits varied among districts and among regions. Polymorphism was high for waxiness (H’= 0.95), lodging resistance (0.91), stem solidness (0.86), glume color (0.80), and fertility of the basal floret (0.80). However, H’ estimates were relatively low for early growth vigor (0.49), seed color (0.44) and juvenile growth habit (0.19). A clinal pattern was observed for resistance to common bunt, Tillelia foetiila (H’= 0.73), stripe rust, Puccinia striiformis (H’= 0.74), and powdery mildew, Erysiphe graminis f.sp. tritici (H’= 0.63). The frequency of resistant entries increased from the xeric south to the mesic north. Average diversity for developmental traits (i.e., days to heading, days to maturity, and filling period) was significantly higher in the semiarid (H= 0.847 ± 0.05) than in the arid (H= 0.658 ± 0.12) location. A hierarchical analysis of variance indicated that significant differences for H’ estimates existed among regions and among districts within regions of collection. Landraces and districts with high frequency of agronomically desirable traits have been identified.