Breakdown of self-incompatibility during pistil development in Lycopersicon peruvianum by modified bud pollination

Abstract

Stylar self-incompatibility barriers in L. peruvianum can be avoided if pollen germination and growth through immature pistils is promoted under specific environmental conditions approximately 2-3 days before the initiation of anthesis. Since immature stigmas lack sufficient exudate for pollen germination, the sandwiching of a thin layer of pollen germination medium between the stigma and a mineral oil layer containing pollen allows precocious pollen germination and some compatible pollen tube growth through the style. This procedure is rapid, inexpensive, applicable in the field, and makes efficient use of pollen. Consistent though low seed yields have been obtained. A high proportion of aborted seed, seedling lethals, and aberrant seedling phenotypes in selfed progeny indicate the presence of strong post-zygotic barriers to such selfing. No evidence for a reduction in the strength of the SI response with increasing pistil age was observed.

Developmental onset of reproductive barriers and associated proteome changes in stigma/styles ofSolanum pennellii

“…The location in the style of reproductive isolating barriers differed between UI and SI, as has previously been reported (Hardon, 1967; Gradziel and Robinson, 1989; Kuboyama et al ., 1994; Liedl et al , 1996; Covey et al , 2010) (Fig. 4).…”

“…In SC accession LA0716, petals begin to separate earlier in bud development, so in this accession stage 0 was assigned to flowers when petals (and anthers) attain full bright yellow color and were completely open. Gradziel and Robinson (1989) also used nodal position as an indicator of bud development in Solanum peruvianum but did not correlate this with the chronological age of the buds. Style length of fresh pistils was measured at each stage (−5 to −1) for each accession (Supplementary Fig.…”

“…Developmental regulation of reproductive barrier establishment is known to occur, since bud pollinations have been used to successfully overcome both interspecific and selfing barriers in many species (Gradziel and Robinson, 1989, 1991; Kuboyama et al ., 1994; Sánchez et al ., 2004; Singh et al ., 2004). For example, UI barriers between cultivated tomato and either Solanum lycopersicoides or S. peruvianum were circumvented by bud pollinations using a stigma complementation procedure on otherwise non-receptive stigmas of pre-anthesis buds (Gradziel and Robinson, 1989, 1991).…”

Sexual hybridization of Lycopersicon esculentum and Solanum rickii by means of a sesquidiploid bridging hybrid.

“…To date, however, there have been no reports of successful use of these hybrids for gene transfer to tomato. By utilizing sexual techniques, however, hybridization and transfer of traits from SS to LL have now been accomplished (2,(9)(10)(11)(12)26). The fact that SS x RR hybrids can readily be obtained, that RS hybrids exhibit regular pairing behavior, and the availability of the LLS hybrid led us to attempt LLS x RR hybridizations.…”

Overcoming unilateral breeding barriers between Lycopersicon peruvianum and cultivated tomato, Lycopersicon esculentum

“…Bud pollination, when applied under proper conditions, can effectively avoid the self-and cross-incompatibility response in styles of Solanum and Lycopersicon (Gradziel & Robinson, 1985, 1989a . A modified bud pollination procedure has been developed which allows selfed seed production in LP lines expressing strict stylar self-incompatibility (Gradziel & Robinson, 1989b (Gradziel & Robinson, 1989b) . All pollinations were made between 9 am and 12 noon during the early spring in Geneva, NY, and over a period of 15 consecutive days to reduce the effects of environmental fluctuations .…”