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EXTRACTION OF ANCESTRAL CONSTITUENTS OF NATURAL POLYPLOIDS. I. PRODUCTION OF PENTAPLOIDS (AABBD) FOR EXTRACTING THE TETRAPLOID (AABB) COMPONENT OF THE HEXAPLOID, TR1T1CUM AESTIVUM

K. A. SlDDIQUI
 

Abstract: To extract ths ancestral tetraploid component, AABB, of the allohexaploid, Triticum aestivum (2n-6x 42), AABBDD, it is necessary to eliminate one genome, that is, one-third of the genotype. An attempt was made to do this by producing pentaploids (2n-5x=35), AABBD, involving 9 standard varieties of T. aestivum (Chinese Spring, Peko, Koga, Svenno, C 591, A.T. 38, April Bearded, C 518 and H-23-42) with 9 tetraploid (2« 4x=28), AABB, varieties of Triticum (Carleton, Mechmudy, Iumillo, Nursi, Samra, Kubankum, T1, 2D 1 and 33 D 1) in a number of combinations. Chinese Spring disomic was the most successful hexaploid parent giving a seed set of 22.5% which was more than 3 times than that found with any other hexaploid parent (1 to 7%). Crosses of the tetraploid variety Machmudy with Chinese Spring disomic produced highest (48 %) seed set. No seed was obtained by crossing a synthetic tetraploid, Triticum monococcum x Aegilops speltoides with varieties (Chinese Spring disomic, Koga and A.T. 38) of T. aestivum.
 

Atomic Energy Agricultural Research Centre, Tandojam.