אסיף מאגר המחקר החקלאי

Inheritance of resistance to stripe rust (Puccinia striiformis) in crosses between wild emmer (Triticum dicoccoides) and cultivated tetraploid and hexaploid wheats. II. Triticum aestivum

Year:

1974

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Volume :

23

Co-Authors:

Grama, A., Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Gerechter-Amitai, Z.K., Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel

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Abstract:

The mode of inheritance of resistance to stripe rust in wild emmer was studied in a series of crosses between Triticum dicoccoides sel. G-25-highly resistant to Puccinia striiformis race 20A-and susceptible cultivars of T. aestivum. In direct crosses between the T. dicoccoides selection and the susceptible T. aestivum cultivars, the pentaploid interspecific hybrids were highly sterile (fertility of 1-2% by self-pollination); the F2 population segregated in a 3 resistant:1 susceptible ratio. In bridge-crosses between the fertile tetraploid progeny of a previous T. dicoccoides-T. durum cross and susceptible T. aestivum cultivars, the fertility was markedly improved (approximately 50% when T. aestivum served as pollinator); the F1 pentaploid hybrids of these three-way crosses segregated in a pattern fitting a 1 resistant:1 susceptible ratio. Results obtained by both of these methods thus prove that a single dominant gene for resistance to stripe rust was transferred from T. dicoccoides sel. G-25 to the susceptible T. aestivum cultivars. In a further cross between T. dicoccoides sel. G-25 and resistant T. aestivum cv. Florence Aurore 8193-the main source of resistance to stripe rust in our wheat-breeding program-the high degree of sterility in the pentaploid interspecific hybrids was overcome by exposing the F1 progeny to open mass-pollination, with Florence Aurore as recurrent parent (seed-set of 1-5%); segregation for stripe rust reaction in the second hybrid generation indicates that a different gene operates in each of the two parents. The F6 populations obtained from crosses between T. dicoccoides sel. G-25 and both susceptible and resistant cultivars of T. aestivum have a high degree of fertility and are considered a valuable stock for wheat breeding. © 1974 H. Veenman en Zonen B.V.

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