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Registration of Seven Related Wheat Germplasms Differing in Irrigation Response
Author(s) -
Lazar M. D.,
Salisbury C. D.,
Worrall W. D.,
Porter K. B.,
Rooney L. W.,
Marshall D. S.,
McDaniel M. E.,
Nelson L. R.,
Tuleen N. A.
Publication year - 1996
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/cropsci1996.0011183x003600030069x
Subject(s) - crop , germplasm , irrigation , forestry , horticulture , agronomy , geography , biology
TX84A18,TX86A5606,TX86A8072,TX88A6880,TXGH10194, TXGH10289, and TXGH10440 (Reg. no. GP-455 to GP-461, P1 587027 to P1 587033) are red winter wheat (Triticum aestivum L.) breeding lines developed by the Texas Agricultural Experiment Station. They resulted from a backcross breeding program conducted by K.B. Porter at Bushland, TX. All have an identical pedigree: ('TAM 105'*4/'Amigo')*4// 'Largo'. Amigo is a wheat-rye translocation line (1AL:1RS) induced by X-irradiation of wheat x triticale FI hybrids (1). Largo is an amphiploid (2« = 6x = 42) from a cross between T. turgidum L. cv. Langdon and T. tauschii (Coss.) Schmal. P1268219 (2). During the first set of backcrosses, in which Amigo was the nonrecurrent parent, selection was practiced for resistance to powdery mildew (Erysiphe graminis DC. f. sp. tritici Em. Marchal), since mildew resistance is linked to Biotype C resistance on the IRS translocation. In backcrosses in which Largo was the nonrecurrent parent, selection was practiced for resistance to Biotype E greenbug [Schizaphis graminum (Rondani)]. In the second set of backcrosses, the recurrent parent (TAM 105*4/ Amigo) was a full sib of the cultivar TAM 107. The coefficient of parentage, rxy (3), can be calculated as a measure of the relatedness of the resulting BCs selections. For any two of these selections, rxy = 0.97. Yield testing of the selections was conducted between 1986 and 1991. Examination of data from irrigated and rainfed locations, in years with large differences between mean rainfed and irrigated yields, indicated a pattern of higher ratios of rainfed yield to irrigated yield for a few lines, and relatively lower rainfed to irrigated yield ratios for others. The two years with the highest rainfall, 1987 and 1988, produced the least differences among lines, while the greatest differences among lines in ratios of rainfed to irrigated yields were observed in the years with the least rainfall, 1986 and 1990. The ratios of rainfed to irrigated yields in these years, as well as in 1991, suggested the possibility that two lines (TX84A18 and TX86A5606) could be less resistant to drought than TAM 107, while three lines (TX86A8072, TXGH10289 and TXGH10440) could be more resistant. A direct comparison among these lines and TAM 107 was conducted in the field at Bushland, TX, during 1992 and 1993. The five lines that had appeared to differ from TAM 107 in ratio of dryland to irrigated yield, TX84A18, TX86A5606, TX86A8072, TXGH10289 and TXGH10440, were compared with TAM 107, along with two other lines of the same pedigree, TX88A6880 and TXGH10194, which had not appeared to differ from TAM 107. Methods employed in these comparisons are presented elsewhere (4). Although significance of the differences among means varied between the two years, the yield ranks, particularly in rainfed production, were quite consistent (4). The relationship between rainfed and irrigated yield may be expressed quantitatively using the susceptibility index, S (5), in which