M. Farhan Ismail
General Commission for Scientific Agricultural Research-
Raqqa Research Center
Aleppo University, Faculty of Agriculture
Nematodes are important pathogens of legumes in Syria, but there are no studies about their importance on lentil especially in presence of vascular wilt caused by Fusarium oxysporum f. sp. lentis. The objectives of this work are
(1) to carry out a survey of lentil nematodes and fusarium vascular wilt in the major growing regions of Aleppo and Idleb provinces to determine their importance, population densities and their relation to fusarium wilt,
(2) to study the influence of various inoculations of the most frequency parasitic sedentary and migratory nematodes genera and their interactions with vascular wilt fungus F. oxysporum f. sp. lentis on growth and yield of Kordy and Hurani lentil Cvs,
(3) to study the life cycle of Heterodera ciceri on Kordy and Hurani lentil varieties under growth room conditions,
(4) screen of 206 cultivated lentil varieties from Syria and its neighbor countries against H. ciceri and it’s interaction with Fusarium vascular wilt, and
(5) to study the influence of manure and sowing date on H. ciceri development and lentil productivity.
Lentil survey showed that H. ciceri and the nematode genera: Pratylenchus, Aphelenchoides, Paratylenchus, Helicotylenchus, Aphelenchus, Tylenchorhynchus and Tylenchus are found to be the most frequency nematodes in the most of the two provinces fields. Also, biometric measurements showed that Pratylenchus thornei distributed at most of the two provinces fields, but P. mediterraneus found in five fields of Idleb, Aphelenchoides dobitus and Tylenchorhynchus tritici distributed at most of the studied fields. Studying the fungus colonies isolated from stems of lentil plants, and their pathogenicity, showed exist of F. oxysporum f. sp. Lentis, and it was most intelligibility in Idleb province’s fields during the flowering and podding stage. As well as, the fungus was associated with the most nematode genera.
Plant height, numbers of pods, biological and seed weight have inversely and significantly correlated with the initial H. ciceri inoculum level, but root weight has significantly increased with the increasing initial inoculum level from this nematode. Also, effect of each migratory lentil nematodes and Fusarium wilt on plant growth and yield are significantly decreased. Interaction between migratory nematodes and Fusarium wilt caused significant influence on plant growth, yield, defoliation and wilt severity on both lentil Cvs. compared to H. ciceri and Fusarium wilt. In addition, interaction between the three groups of nematodes and Fusarium wilt resulted in a significant failure of plant growth, and raised wilt severity and finally plant death of the two lentil varieties.
Final population and reproduction of H. ciceri have inversely correlated with its initial inoculation level, and both nematode groups are significantly decreased to the lowest level when existed together with Fusarium wilt in root.
Under growth room conditions, second stage juvenile of H. ciceri started invasion the root of two Kordy and Hurani lentil cultivars one day before seedling emergence. The nematode completed its life cycle during 50 day of inoculation. Also, second generation of this nematode developed with low specimens on Hurani cultivar compared to the first generation. Second stage juveniles emerging and lentil root invasion delayed 5 days later than first generation, and they was unable to reach mature shiny reddish brown cysts, and they were in the beginning formation of white reddish cysts at the plant maturity.
All 206 lentil cultivars screened under plastic house conditions found to be susceptible to H. ciceri nematode, whereas 103 cultivars of them were resistant to Fusarium wilt, decreased to 14 cultivars with moderately resistance to the interaction between two pathogens. Infection with any of the two pathogens alone or together didn’t affect the days to flowering with all cultivars. But interaction between the two pathogens significantly decreased the days to plant maturity more than each pathogen alone.
The same was found with plant height, number of pods, biological plant and seed weight. In addition, infected seeds were small, discolored, warped and curled. Fusarium wilt decreased the root weight of all Cvs. compared to the check plants. Inversely, root weight has significantly increased by H. ciceri infection compared to the interaction between the two pathogens. Also, infected root with H. ciceri gave special smell like a moldy fish, decreased when existed together with Fusarium wilt. Final population and reproduction of H. ciceri decreased to the lowest level when existed together with Fusarium wilt in lentil roots.
Biological weight and plant height positively correlated with earliness of sowing date, from the first to the last one without considering existence or absence of manure or cyst nematode. Lentil productivity parameters: plant height, biological weight, number of pods, root and seed weight significantly increased with organic manure.
Inversely, organic manure significantly reduced influence of H. ciceri at all lentil productivity parameters without considering the sowing date.
So, these parameters appeared significantly higher than their absence. Also, manure significantly decreased the final population and reproduction of H. ciceri in all studied sowing dates, except for the first date which appeared significantly higher with manure existence compared to its absence.
Influence of H. ciceri with manure existence on each of plant height, biological and seed weight was the same on the first and second dates compared to the check plants on the second and third dates. The same was found with the number of pods at second date compared to the check at the second and third dates.