Inheritance Of Stem Rust Resistance Research Articles

Inheritance of stem rust resistance in Indian bread wheat cultivars

Four Indian bread wheat cultivars viz., DL788-2, GW322, Raj3765 and UP2425 were genetically analyzed against three selected pathotypes 21 (9G5), 40A (62G29) and 117A (36G2) of Puccinia graminis tritici at Indian Agricultural Research Institute, New Delhi. The segregation pattern in seedlings of F2 derived from crosses with Agra Local as susceptible parent showed the presence of three dominant independent genes for stem rust resistance in DL788-2 and Raj 3765, and two dominant independent genes in each GW322 and UP2425 when analyzed with pathotype 21 (9G5). These findings were supported by segregation of F2 seedlings of reciprocal crosses (AL x parent), in same pattern and reconfirmed by analyses of BC1 and BC2 progenies to test pathotypes. The F2 seedlings of all the diallele crosses did not segregate for susceptibility to pathotype 21 (9G5). It indicated that resistance gene(s) may be common in test cultivars, however, some of the diallele crosses showed segregation to pathotypes 40A (62G29) and 117A (36G2) showing dissimilarity of resistance. Genes Sr24in DL788-2, Sr1 1 in GW 322 and Sr31in UP2425 were validated based on pedigree and infection types of cultivars, and confirmed by test of allelism. An adult plant resistance gene Sr2was also identified in all these test cultivars based on mottling effect in the seedlings.

Inheritance of Stem Rust Resistance and Some Yield Components in Crosses from Five Egyptian Wheat Cultivars

Inheritance of Stem Rust Resistance and Some Yield Components in Crosses from Five Egyptian Wheat Cultivars

Studies of the genetics of inheritance of stem rust resistance in bread wheat

Pgt race TTKSK (Ug99) has a wide virulence range with respect to currently grown wheat cultivars worldwide. Aspects of migration, mutation, recombination and selection in the pathogen have led to previously deployed stem rust resistance genes being ineffective. Race TTKSK has further evolved to acquire virulence for resistance genes such as Sr24 (race Ug99 + Sr24) and Sr36 (Ug99 + Sr36). Five resistant wheat lines (KSL-2, KSL-3, KSL-5, KSL-12 and KSL-19) which were resistant in tests during 2008, 2009 and 2010 were used as parents in crosses with stem rust susceptible line CACUKE to develop genetic populations for determining the inheritance of resistance to stem rust. F3 populations were evaluated at KARI Njoro in the 2012 off season and 2012 to 2013 main season. The adult plant stem rust responses were scored using the modified Cobb’s scale. The F2:3 lines of population(s) exhibiting qualitative variation were grouped as homozygous resistant (HR), segregating (Seg) and homozygous susceptible (HS). Heavy disease pressure was present during the cropping seasons with the check CACUKE displaying 90% susceptibility. Chi square analysis revealed that the segregation data in the parent KSL-2 did not deviate significantly from the single gene model (1:2:1) suggesting that the resistance to stem rust is conditioned by a single dominant gene. The Chi square test also revealed that the stem rust resistance in the parents KSL-3, KSL-5, KSL-12 and KSL-19 was conditioned by two genes. The families from the KSL-2 and KSL-3 crosses also segregated for the presence of the pseudo black chaff implying that the Sr2 gene could be present in the background of these wheat parents. The superior transgressive segregants identified in these crosses will be used in breeding. Keywords: Genetic, wheat, gene, resistance African Journal of Biotechnology Vol. 12(21), pp. 3153-3159

Inheritance of stem rust resistance derived from Aegilops triuncialis in wheat line Tr129

Ghazvini, H., Hiebert, C. W., Zegeye, T. and Fetch, T. 2012. Inheritance of stem rust resistance derived from Aegilops triuncialis in wheat line Tr129. Can. J. Plant Sci. 92: 1037–1041. Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a devastating disease of wheat that can cause serious grain yield reduction. The emergence of Pgt race TTKSK (Ug99) and new variants in Africa is considered a threat to wheat production worldwide. Among the primary gene pool of wheat, only a few stem rust resistance (Sr) genes confer resistance to TTKSK. Wild relatives of common wheat are an important source of disease resistance. A preliminary study indicated that the common wheat line Tr129, which contains one or more Aegilops triuncialis translocations, is resistant to race TTKSK. The goal of this study was to elucidate the inheritance of resistance to Pgt in line Tr129 and investigate the novelty of the gene(s) conferring resistance. A population was generated by crossing RL6071 with Tr129 and F2 and F3 progeny were inoculated with Pgt race MCCF at the first leaf stage. Segregation of F2 plants fit a 15:1 ratio ([Formula: see text]=1.48, P=0.22) indicating two dominant genes in Tr129 conditioned stem rust resistance to race MCCF. Segregation of F3 families also fit a 7:8:1 ratio ([Formula: see text]= 3.28, P=0.19) confirming the presence of two dominant genes. This is first report of stem rust resistance transferred to wheat from Ae. triuncialis.

Inheritance of resistance to oat stem rust in the cultivars Ronald and AC Gwen

Mitchell Fetch, J. and Fetch Jr., T. 2011. Inheritance of resistance to oat stem rust in the cultivars Ronald and AC Gwen. Can. J. Plant Sci. 91: 419–423. Oat stem rust, caused by Puccinia graminis Pers. f. sp. avenae Eriks. and E. Henn., causes sporadic epidemics and yield losses in Manitoba and eastern Saskatchewan. Oat (Avena sativa L.) cultivars registered for production in this area possess resistance to stem rust, but their genetic composition is unknown. Race TJJ (NA67), first detected in 1998, is virulent on most Pg genes; thus, it is desirable to know the gene(s) that are present in currently grown oat varieties. The hulled cultivar Ronald and the hulless cultivar AC Gwen were selected for characterization of inheritance of stem rust resistance, and crossed to the susceptible cultivar Triple Crown. Race BLD (NA1) was used to evaluate F1 plants and F2 populations. All F1 plants were resistant, indicating the presence of at least one dominant gene. Pooled F2 populations fit a 13:3 (resistant:susceptible) ratio for both Ronald (χ2 =0.31, P =0.58) and AC Gwen (χ2 =3.32 and P =0.07), indicating the presence of one dominant and one recessive gene. Segregation ratios in pooled F3 families fit a 7:8:1 (homozygous resistant:segregating:homozygous susceptible) ratio with race BLD (χ2 =0.84, P =0.66 for Ronald; χ2 =1.99, P =0.37 for AC Gwen), a 1:2:1 ratio (segregating families with 1:3 ratio) with race TJD (χ2 =2.87, P =0.24 for Ronald; χ2 =3.45, P =0.18 for AC Gwen), and a 1:2:1 ratio (segregating families with 3:1 ratio) with race FDJ (χ2 =1.33, P =0.51 for Ronald; χ2 =2.04, P =0.36 for AC Gwen). These results and reactions to known races of Puccinia graminis f. sp. avenae indicate that both Ronald and AC Gwen possess the dominant gene Pg2 and recessive gene Pg13. This genetic study characterized the stem rust resistance in Ronald and AC Gwen, and confirmed the limited base of stem rust resistance in Canadian oat cultivars.

The inheritance of stem rust resistance in Thatcher wheat

Thatcher was the predominant wheat (Triticum aestivum L.) cultivar on the Canadian prairies in the 1950s. Until race 15B (TMH) of stem rust (Puccinia graminis pers. f. sp. tritici Eriks. & Henn.) became widespread, Thatcher had good resistance to stem rust, but was susceptible to leaf rust (P. recondita f. sp. tritici Rob. ex Desm.). Although genes for stem rust resistance have been identified in Thatcher, the inheritance of its resistance has never been fully understood. The objective of this research was to attempt to elucidate the inheritance of the resistance of Thatcher and to determine why it had a reputation as a poor parent for rust resistance. Over a period of 40 yr, crosses and backcrosses to a susceptible genotype and two sets of single seed descent (SSD) lines were studied. The second set of SSD lines was tested with isolates of six races of stem rust to which Thatcher is resistant. The data showed that Thatcher is a very heterogenous cultivar with individual plants differing widely in the genes for stem rust resistance that they carry. The inheritance of rust resistance varied greatly from race to race and was often quite complex. Either complementary genes or a gene plus a suppressor appeared to condition resistance to one race. Most genes gave resistance to only one race. The presence of Sr5, which Thatcher is known to have obtained from Kanred, was confirmed. Most of its many additional genes probably came from Iumillo durum wheat. Key words: Stem rust, Thatcher wheat, single seed descent

Inheritance of Stem Rust Resistance in ‘Webster’ Wheat1

Inheritance of seedling resistance to stem rust (Puccinia graminis f. sp. tritici Eriks. & E. Henri.) in ‘Webster’ wheat (Triticum aestivum L.) was studied in testcrosses and in crosses with the ‘Chinese Spring’ monosomics. Studies in Canada and Australia showed that its resistance to several North American and Australian races of stem rust is controlled by the same nearly recessive gene, which is designated Sr30. Analysis of the monosomic crosses indicated that Sr30 is on chromosome 5D.The cultivar ‘Festiguay’, which also carries Sr30, was crossed with a Chinese Spring 5DL ditelocentric line, a 5DL ditelocentric line in which the telesomes carried Lrl, and a euploid marker stock homozygous for Lrl and Pm2. The results of these crosses indicated that Sr30 is on the long arm of chromosome 5D and is probably independent of the centromere, Lrl and Pm2. Pm is presumed to be on the short arm, with the order being Pm2 — the centromere — Lrl — Sr30.

Tetrasomic Inheritance of Stem Rust Resistance in Orchardgrass

Tetrasomic Inheritance of Stem Rust Resistance in Orchardgrass

DIFFERENTIAL FERTILIZATION IN THE INHERITANCE OF STEM RUST RESISTANCE IN HYBRIDS INVOLVING A COMMON WHEAT STRAIN DERIVED FROM TRITICUM TIMOPHEEVI

DIFFERENTIAL FERTILIZATION IN THE INHERITANCE OF STEM RUST RESISTANCE IN HYBRIDS INVOLVING A COMMON WHEAT STRAIN DERIVED FROM TRITICUM TIMOPHEEVI