The production of aneudihaploids in Solanum tuberosum L. group Tuberosum (the common potato)

Abstract

Trisomic cytotypes were produced in dihaploid (diploid) plants of Solanum tuberosum L. Group Tuberosum, the common potato, according to two methods. Firstly, the aberrant types were selected, through chromosome counting, from parthe.nogenic dihaploid offspring of tetraploid-diploid crosses. In dihaploid populations from twelve tetraploid potato varieties the frequencies of aneuploids ranged from 3.5 to 11.0~g. About 95~ of these aneuploids had only one, and the others not more than two extra chromosomes. Secondly, the aneuploids were produced from triploid-diploid crosses. Seedset strongly depended on the crossability of the parental plant material, and the best results were obtained when the motherplants were grafted onto tomato. On avarage the three most successful cross combinations resulted in approximately 0.7 berries per pollination and 6 seeds per berry. With regard to seedsize the seed could be divided in two groups, viz. normal and small seeds. Half of the seed did not germinate or produced inviable seedlings, especially among the small seed group. About 93~, of the plants was aneuploid, with 25, 26 and 27 being the predominant chromosome numbers. It was concluded that the production of trisomics was the most successful through triploid-diploid crosses. The results were discussed with reference to the chromosomal behaviour in the meiosis in triploid plants (LANGE & WAGENVOORT, 1973a). It thus was possible to relate the low seedset to the distribution of chromosomes in the meiotic anaphases. On the one side this distribution resulted in a limitation of the availability of gametes with monohaploid and near-monohaploid chromosome numbers, while on the other side the macrospores with higher chromosome numbers seemed to be inviable. Finally a crossing scheme was presented for transmitting the trisomic condition into a genetic background with better homogeneity and more homozygosity.

Spontaneous structural rearrangements in Solanum tuberosum ssp. phureja: 1. Chromosome identification at pachytene stage

“…The anthers were stained in alcoholic hydrochloric acid carmine for 16-24 h at 60'C according to the method of Snow (1963) and squashed in a drop of 45% acetic acid . The methods used to study mitotic chromosomes were the same as described by Wagenvoort & Lange (1975) .…”

Post-zygotic gametic selection due to endosperm balance number explains unusual chromosome numbers of 3� � 2� progeny in Solanum

“…Larger numbers of extra chromosomes are not recovered because gametophytes and/or zygotes cannot usually survive high chromosome imbalances (Khush 1973). In Solanum, 3× × 2× progenies, involving triploids derived from 2EBN diploids, normally came close to the chromosome number of the diploid parent (Vogt and Rowe 1968;Lee et al 1972;Wagenvoort and Lange 1975). However, 3× × 2× crosses with triploids derived from the sexually isolated 1EBN species S. commersonii (2n=2×=24) (cmm) gave unusual results, in that the chromosome number of the progeny was close to that of the triploid parent (von Oláh 1938;Elhenfeldt 1984).…”

Identification of the trisomic series in diploid Solanum tuberosum L., group tuberosum. I. Chromosome identification

“…HERM-SEN (1973) developed two very fertile dihaploids, G 609 and G 254, and crossed them with 'Gineke' tetraploid, and triploid plants were obtained. A number of these triploid plants were crossed with G 254 by WAGENVOORT & LANGE (1975) for producing aneuploids. Twenty one trisomics (2n 25) from these aneuploids, together with the dihaploids G 609 and G 254, were investigated in this study.…”