Somaclonal variation in tuber disc-derived populations of potato
Abstract
Potato (Solanum tuberosum L.) plants, numbering in the thousands, were regenerated in vitro from meristems adventitiously initiated on tuber disc explants. Direct regeneration from tuber disc cells, bypassing the initiation of callus, was an efficient procedure, was applicable to numerous cultivars, and resulted in low frequencies (below 1.5%) of gross aberrations in the regenerated plants. An initial somaclonal population of the cultivar Superior was statistically characterized in field plots over five asexual generations and in three diverse locations. When compared to a large population of control plants propagated from stem cuttings, the means of the somaclonal population were significantly different, often shifted in the desirable direction, for 16 of 22 horticulturally important traits. Somaclonal population variances statistically exceeded those of the controls for 13 of the 22 traits. As a result of adventitious regeneration, there were considerable differences in variability for several traits. Heritability values calculated for tuber elongation ratio, total tuber number, and total tuber weight were 0.56, 0.23, and 0.10, respectively. Regressions between consecutive tuber generations and between locations or replications (blocks) within a generation were significant in the somaclonal population for all traits analyzed. In a few instances, significant control population regressions occurred which were the result of non-random, non-genetic factors primarily affecting control plants of low vigor. Selected somaclones exhibiting desirable alterations for yield, tuber number and shape, and vigor demonstrated stability over more than two consecutive asexual generations. Data on somaclonal populations regenerated from three cultivars provided evidence of a significant genotype effect. Regenerated populations of 'Kennebec' and 'Superior', cultivars which share a common parent, were similarly enriched with somaclones having more enlongated tubers, higher total tuber number and weight, greater cull tuber number and weight, and earlier maturity. Somaclones of 'Russet Burbank' also produced more elongated tubers, higher total tuber number, and higher cull tuber number and weight, but in contrast these somaclones were lower in total tuber weight, lower in U.S. 1 tuber number and weight, shorter in stem length, and lower in vigor. Of the three cultivars, 'Russet Burbank' somaclones possessed the greatest variability for most traits.
Degree
Ph.D.
Advisors
Bressan, Purdue University.
Subject Area
Genetics|Plant propagation
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