مورثات وبعض آليات المقاومة لحشرة حافرة أوراق الحمص

Abstract

Chickpea leaf miner Liriomyza cicerina Rondani is the most important insects affecting chickpea. The use of resistant varieties for controlling the pestʼs populations is considered one of the best control methods. This research work aimed at evaluating 8 chickpea lines in two seasons, studying the relationship between the concentrations of some organic acids and the resistance to chickpea leaf miner, identifying the qualitative traits Loci (QTL) that are responsible for resistance to chickpea leaf miner. The experiments were carried out at Tel Hadyaʼs Research Station of the International Centre for Agricultural Research in the Dry Areas ICARDA –Aleppo, during 2011-2012 cropping seasons, in both winter and spring sown. Eight lines having different resistance levels to insect were planted, the degree of damage was estimated using 1-9 scale, where 1 = no leaf miner infection; and 9 = many tunnels on all the leaves. In the first growing season of 2011, lower damage ( 2.75) was recorded on the resistant line ILC 5901 in both winter, and spring sown chickpea, while the highest degree of damage (7.25, 8.25) were recorded on the susceptible line ILC 3397 in both winter, and spring sown chickpea, respectively. In the second growing season of 2012, the least damage score ( 2.7, 2.73) were recorded on the resistant line ILC 5901 in both winter, and spring sown chickpea, respectively, The highest degree of damage (7.4, 7.5) were recorded on the susceptible line ILC 3397 in both winter, and spring sown chickpea, respectively. The selection FLIP 2005-3 produced the highest seed and biomass yields in both winter and spring sown chickpea in the two seasons, the seed yield was 904, 478 Kg/h, in winter and spring growing seasons 2011, respectively, and the biomass yield was 3146, 930 Kg/h, in winter and spring growing seasons 2011, respectively, and the seed yield was 937, 629 Kg/h, in winter and spring growing seasons 2012, respectively, and the biomass yield was 2696, 945 Kg/h, in winter and spring growing seasons 2012, respectively. The seed and biomass yields of the accession ILC 3397 varied depending on natural infestation and caged planting, while the accession LC 5901 produced approximately equal yields in both planting types. The results also showed no significant differences in harvest index between accessions, while infestation severity was negatively correlated with seed and biomass yields. The lowest loss percentage was recorded when the accessions ILC 5901 and ILC 3805 were planted. The use of resistant cultivars in IPM programs for the Leaf miner management is to be encouraged. Hybridization was performed between the resistant (ILC 5901) and susceptible (ILC 3397) lines, resulting in 15 plants in the first generation, that gave about 800 seed, out of which 400 seed were randomly selected and planted in the field and the degree of damage were estimated. This study showed general weakness for the sources of genetic resistance, where the percentage of resistant plants were 10%, that of moderately resistance 29.4%, and that of moderately susceptible 20%, and percent of susceptible plant amounted to 40%. The resistance and moderately resistance plants were characterized with multipinnate leaves and narrow flat size, while the susceptible plants were characterized by normal leaf type and wide size. All external surfaces of the chickpea plants, are covered by a glandular hairs that secrete acids, that contribute to reduce the damage, High Performance Liquid Chromatography used to identify these acids and their concentrations was tested> significant differences in the concentration of oxalic acid between the resistant and susceptible lines were found. The concentration of oxalic acid in the resistant line ILC 5901 was 2.29 and 2.22 mg/100g leaves, in the two seasons 20112012, respectively.

Whereas in the susceptible line ILC 3397, the concentrations of oxalic acid were 1.52 and 0.1 mg/100g leaves, in the two seasons 2011-2012, respectively. There was a significant negative correlation between the concentration of oxalic acid and the damage caused by leaf miner, and this is an indication of its role in resistance. Out of 500 simple sequence repeats (SSR) markers tested on the parents, only 51 showed polymorphisms and could be used to generate a genetic map. QTL analysis indicated four QTLs conferring LM resistance on linkage group LG1 (TA37), LG3 (TA34), LG4 (H4F03) and LG8 (NCPRG 89) explaining 9.6-22.2% of the LIS (leaf infected scale) variations. Interestingly, two unmapped markers (NCPRG 48, H1C092) were strongly linked to leaf infected scale (LIS) explaining 55.3%, 26.8% of the LIS variation, respectively. These markers showed dominance (skewed) toward the susceptible parent. This is the first report of the use HPLC and SSR markers associated with LM resistance in chickpea which might help guiding and improving the use of marker assisted selection to speed up the conventional breeding of LM resistance in chickpea.