Selection from Solanum tuberosum group phureja of genotypes combining high-frequency haploid induction with homozygosity for embryo-spot

Abstract

In this article the term `pollinators' refers to diploid genotypes of Solanum tuberosum Group Phureja which are used to pollinate autotetraploid potatoes for the induction of autonomous growth of unfertilized egg cells . Plants obtained from such egg cells contain chromosomes of the female only and are called dihaploids . The successful selection of ideal pollinators from Group Phureja is described . A pollinator is considered to be ideal, if it has good male fertility, homozygosity for the dominant seed marker embryo-spot and the ability to induce in autotetraploid cultivars a high number of dihaploids both per berry and per 100 seeds. Embryo-spot is a deep purple or reddish coloration at the base of the cotyledons of the embryo, visible on both sides of the flat seeds . It is one manifestation of a set of complementary genes with pleiotropic action, causing a concentration of anthocyanins at the base of all plant organs that are homologous to leaves . The complementary genes are : a basic gene P for anthocyanin production (this is the seedling marker `coloured hypocotyl') and allele B°o f locus B . Thirty-three homozygous B°B°PP plants and 41 B°bPP plants were identified and a number from both classes tested as pollinator onto varieties .Among the homozygous group a number of `ideal pollinators' could be detected . Unexpectedly a few polyploids grew from spotless seeds when using homozygous pollinators on varieties ; 1 .4% showed purple hypocotyl and 2 .6 % were matroclinous. The latter group of polyploids probably may have arisen from `unreduced' egg cells of the cultivars used .In the progenies from crosses between recessive cultivars (bbbbpppp) and heterozygous pollinators (B°bPP) the ratio of spotted : spotless hybrid seeds appeared to deviate greatly from 1 :1 . This is ascribed to `unreduced' gametes, which originate during meiosis, presumably through lack of formation of the 'reductional' (= first division) cell wall . On this assumption a map distance of 30 and 24 cross-over units is estimated for locus B on the basis of the proportion of nulliplex tetraploid hybrids in two different crosses .High-and low-seed-set pollinators were found at a ratio of 8 :21 suggesting monogenic dominance of low seed-set. Seeds per berry and haploids per berry are significantly correlated using low-seedset pollinators on cultivars, but they are not when pollinators are used that produce high numbers of seeds per berry . A hypothesis is put forward to explain this phenomenon .

A Tetraploid Induction in Hypericum patulum Thunberg by Colchicine Soaking Treatment

“…'embryo maker' 등 표식유전자 (Bingham, 1969;Hermsen and Verdenius, 1973), 기공세포 (Borrino and Powell, 1987), 기공내 엽록체 수 (Chaudhari and Barrow, 1975;Dudley, 1968;Bae et al, 2001), 화분립 (Bamberg and Hanneman, 1991)의 관찰 등이 있으나, 주로 가장 정확한 방법으로 알려진 염색체 수 및 세포내 DNA의 양에 의한 분 석방법이 이용되고 있다 (Galbraith et al, 1983;Miyoshi and Asakura, 1996;Sari et al, 1999) 인용문헌…”

Functional Genomics For Crop Improvement

“…The observation that in wide crosses of Hordeum vulgare × Hordeum bulbosum elimination of the latter set of bulbosum chromosomes occurred (Kasha and Kao 1970), augured well for producing doubled haploid plants and the barley system has extensively been used in barley breeding programs worldwide. Other examples of wide crosses for doubled haploid production based on chromosome elimination include wheat x maize for production of doubled haploid durum wheat (Sarrafi et al 1994) and Solanum tuberosum × S. phureja (Hermsen and Verdenius 1973). With advances in tissue culture, haploid plant can now be regenerated from in vitro cultured microspores with high efficiency in many plant species for incorporation in breeding programs.…”

DEVELOPMENT OF INITIAL MATERIAL FOR MARKER ASSISTED POTATO (Solanum tuberosum L.) PARENTAL LINE BREEDING AT THE DIPLOID LEVEL (review)

“…Dutch forms of S. phureja, IvP 35, IvP 48 and IvP 101, combining high ability to produce haploids with homozygous state of the embryo-spot marker gene responsible for seed lobe anthocyanin coloring, are the most widely used in potato breeding [6]. The embryo-spot is easily detected by a binocular microscope, so introduction of the said haploproducers in the breeding practice made it possible to identify potato dihaploids (by absence of a marker trait) with minimum labor effort.…”