EVALUATION OF FUSARIUM CROWN ROT DISEASE (FUSARIUM CULMORUM) RE​SISTANCE IN JORDANIAN DURUM WHEAT LANDRACES

HUDA A. AL-HYARI¹, AYED M. AL-ABDALLAT², KHOLOUD M. ALANANBEH¹

¹ Department of Plant Protection, School of Agriculture, The University of Jordan, Amman 11942, Jordan, and ² Department of Plant Sciences, School of Agriculture, The University of Jordan, Amman 11942, Jordan. ³ Correspondence: a.alabdallat@ju.edu.jo.

Fusarium crown rot (FCR) disease, caused by a complex of Fusarium species, is one of the major diseases affecting wheat production worldwide and particularly in dry areas. Durum wheat (Triticum turgidum L. ssp. durum) production suffer significant yield losses due to FCR. Nowadays, climate change plays an important role in increasing disease severity and aggressiveness of FCR that is associated with drought and hot conditions. Utilization of durum wheat landraces in breeding programs is considered a promising strategy to identify new sources of resistance against FCR. Therefore, the main objectives of this study were to evaluate the response of selected Jordanian durum wheat landraces against F. culmorum infection under controlled and field conditions and to identify new genetic resources for resistance against F. culmorum in a selected set of Jordanian durum wheat landraces. For this purpose, a set of 24 Jordan durum wheat landraces with two checks (with known resistant reactions: moderate and susceptible)) were evaluated for their responses to F. culmorum infection under controlled conditions (germination stage by using Petri-dish test and seedling inoculation in greenhouse experiments by using three colonized grains and colonized grains- soil mix) and under natural infested field conditions. Different parameters were considered at germination stage that included germination percentage (G%), germination rate reduction (GR), coleoptile length (CL), coleoptile length reduction (CLR), radical length (RL), number of seminal roots (SRN), longest seminal root (LSR) and the Standardized Area Under Disease Progress Curve (AUDPC_standard). At seedling stage germination percentage (G%), FCR score, seedling height (SH), and disease index (DSI) were evaluated. For field trials, plant height (PH), peduncle length (PL), total weight (TW), grain weight (GW), spike number (SN/ m2), spike weight (SW), spike length (SL), spikelet number, grains per spike (G/S), and kernel characteristics and FCR score, and disease index (DSI) were recorded. At the germination stage, F. culmorum had negative effects on most of studied parameters. The AUDPC_standard parameter showed that 14 out of 25 genotypes were found to be tolerant, four moderately susceptible and seven were highly susceptible. Using the three colonized grains assay at the seedling stage, only four genotypes were found to have moderate tolerant against FCR, while seven genotypes had moderate tolerant when the colonized grains soil mix assay was used. Results of the genotypes reaction under natural infected field identified a wide range of variability and effect of Fusarium on agronomic traits at adult stage that varied among genotypes. Out of the nine genotypes tested including the two checks, two genotypes were found to be moderately tolerant and Fusarium infection had a little effect on agronomic traits especially on total kernel weight (TKW). The reaction of these two genotypes were semi-consistent at the three stages (germination stage, seedling, and adult). Therefore, these two genotypes could be utilized to develop new FCR-resistant genotypes in durum wheat breeding programs and for the mapping of quantitative trait loci (QTL) associated with FCR resistance. ​