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Association between Gene Lr34 for Leaf Rust Resistance and Leaf Tip Necrosis in Wheat
Author(s) -
Singh Ravi P.
Publication year - 1992
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1992.0011183x003200040008x
Subject(s) - biology , puccinia recondita , cultivar , rust (programming language) , germplasm , necrosis , botany , agronomy , horticulture , genetics , computer science , programming language
Durable resistance to leaf rust ( Puceinia recondita Roberge ex Desmaz. f. sp. tritici ) in bread wheat ( Triticum oestivurn L.) cultivars is known to result from the interaction of Lr34 with other minor additive genes that are effective in the adult growth state. The Lr34 gene seems to be present in several CIMMYT germplasm‐derived Mexican cultivars that display temperature‐ and light‐sensitive seedling responses similar to those displayed by near‐isogenic ‘Thatcher’ lines that contain Lr34 . Adult plants of these two Thatcher lines and all Mexican cultivars postulated to carry Lr34 display resistance to leaf rust and exhibit leaf tip necrosis symptoms. This study was conducted to determine whether 15‐34 and a gene or genes for leaf tip necrosis am linked. The simultaneous presence of Lr34 and leaf tip necrosis in the two Thatcher near‐isogenic lines and Mexican cultivars was confirmed by evaluating F 2 plants or F 3 lines obtained from various intercrosses. Lr34 and leaf tip necrosis were inherited together in a population of 117 F 3 lines obtained from the cross of leaf rust resistant ‘Jupateco 73R’ (carrying Lr34 and leaf tip necrosis) with its susceptible counterpart ‘Jupateco 73s’. Linkage or pleiotropism was also evident in the crosses of six Lr34 ‐carrying Mexican cultivars with ‘Siete Cerros 66’ (which does not have Lr34 ). The gene for leaf tip necrosis, designated Lln , could be used as a marker for Lr34 .