DURABLE RESISTANCE TO LEAF RUST IN SOME EGYPTIAN WHEAT CULTIVARS

Abstract

The levels of field resistance, which are known as partial resistance to wheat leaf rust, caused by Puccinia triticina were studied at adult plant stages, to show the durability and stability of Egyptian wheat cultivars during the period from 2012 to 2016. A wheat cultivar to, posses leaf rust durable resistance, must undergo some tests to prove its durability. In this study fourteen tested wheat cultivars were grown under field conditions at four locations in. Kafr-Elsheikh, Behira, Sharqia and Beni Swef governorates during four successive growing seasons (2012/13-2015/16).The final rust severity (FRS%), (r- value) and (AUDPC) were found to be of lower values in wheat cultivars, Gemmiza 12, Sids 12, Sids 13, Misr 1, Misr2, Giza 168, Giza 171 and Sakha 94, These cultivars are characterized and believed to have durable resistance to leaf rust. Under greenhouse conditions the wheat cultivars Gemmiza 12, Sids 13, Giza 168, Giza 171 and Sakha 94 had longest incubation period (12 days) and latent period (13-15 days) in addition to they exhibited, the lowest values of pustules denisity cm2 ranged from (5.00 to 15 cm2) and pustule size (mm2), ranged from 0.023 to 0.088 mm2. These five cultivars could be characterized as highly resistance to leaf rust. Thirteen cultivars were identified by moluaclar marker for Lr13, Lr34 and Lr46 data showed that the wheat cultivars Giza 168 and Giza 171 carry the three genes of durable resistance Lr13, Lr34 and Lr46, followed by cultivars i.e. Gemmiza 9, Gemmiza 10, Gemmiza 12, Sids 12, Sids 13, Misr 1, Misr 2 and Sakha.94 which carry two durable resistance genes Lr34 and Lr46. Crosses between the nine wheat cultivars and the two durable resistance genes to leaf rust Lr13 and Lr46 showed the presentence of Lr13 in the two cultivars, Gemmiza 10 and Sakha 94 and Lr46 in four cultivars Misr 1, Misr 2, Sids 12 and Giza 171. Genotypes including Sids13, Sakha 94, Giza 168 and Gemmiza 12 which are as stable cultivars according to consideration of the two stability parameters.The effect of leaf rust infection on grain yield showed that wheat cultivars Misr 2, Sakha 94 ,Sids 12, Gemmiza 9 and Gemmiza 10 showed lower levels of final rust severity (FRS) and area under disease progressive curve (AUDPC), which exhibited lower levels of total and actual yield losses % ranged from (2.47 to 10.31%) and (1.25 to 5.90%) to both respectively in the thousand kernel weight and from (2.46 to 11.43%) and (1.24 to 3.93%) in yield per plot. While Gemmiza 7 and T.S.S showed the highly level of (FRS%) and (AUDPC) which exhibited high values of total and actual loss% (12.72% and 19.30%) and (10.71% and 10.76%) in the thousand kernel weight to both respectively while in yield per plot were (21.68% and 21.21%) and (21.68% and 9.98%) respectively, and were characterized as fast rusting or highly susceptible wheat cultivars. Resistance genes Lr9, Lr19, Lr34 and Lr46 which exhibited the least levels of rust severity% ranged from 0 up to 10MR-MS at the multi-locations (governorates) and during the three growing seasons of the study. These four resistance genes could be characterized as more effectiveness and stability against wheat leaf rust.. The quantitative analysis of the F1 and F2 leaf rust severity showed that the heritability values for all the tested crosses are considered to be higher, ranged from 84.78%, to 97.2%,