PJB-2019-866
LEAF RUST RESISTANCE STATUS IN WHEAT GERMPLASM ASSESSED THROUGH MOLECULAR MARKERS AND MULTI-LOCATION FIELD TESTING
Muhammad Ismail
Abstract
Wheat leaf rust (caused by P. triticina) is the best controlled through sustainable deployment of genetic resistance, which requires rigorous testing through field testing and marker assisted selection. A set of 28 exotic lines with three check varieties (Siran, Atta-Habib, Ghanimat-e-IBGE) were tested at three contrasting locations, along with molecular screening with three Lr genes. Overall leaf rust pressure was low during the wheat season of 2015-16, with maximum at Lakki-Marwat (up to 70%), followed by Peshawar (up to 50%) and minimum at Mansehra (up to 30%). The tested germplasm had variable resistance level as revealed through ACI (average co-efficient of infection); where 16 out of 28 genotypes were completely resistant, while few genotypes showed partial resistance. The maximum CI value was recorded for wheat line W-SA-87, which was 55 at Lakki Marwat, 33 at Peshawar and 15 at Mansehra, while several (18) lines had CI value of zero across the three locations. Variability existed in yield parameters with W-SA-84 (466 g per 4.5 m2 plot), W-SA-78 (443 g) and W-SA-79 (431 g) producing the better grain yield among the advance lines. Molecular genotyping revealed that STS-7 (linked with LrPr) was the most frequent (83.8%), present in 26 lines; followed by SC-Y15 (linked with Lr37) present in 24 lines (77.4%), while csLV34 (linked with Lr34) was present in 16 lines (71.1%). Interestingly, in 45% of the studied germplasm all three of the resistant genes were identified. Cluster analysis resulted in four clusters, grouping different wheat lines on the basis of both phenotypic (disease severity and production of yield parameters) and molecular genotypic data. These results must be useful for crossing and selection of resistance lines to eliminate the leaf rust disease and ensure higher wheat yield.
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