Phills, B. R., and R. W. Robinson Flowering of Solanum lycopersicoides and its hybrid with the tomato. Solanum lycopersicoides is refractory to flowering under greenhouse conditions. It flowers profusely in the field in New York and Alabama commencing late in the season but continuing until very late in the fall, long after the advent of cold weather which inhibits growth and development of tomatoes. But it is often vegetative in the greenhouse during the winter months especially where light intensity is low. Poor flower production in the greenhouse appears to be a dominant trait; the L. esculentum x S. lycopersicoides hybrid flowers even more infrequently in the greenhouse than its parents. A series of tests were made in the greenhouse and in growth chambers to find a way to stimulate flowering of the intergeneric hybrid and its wild parent. Grafting the hybrid to a tomato rootstock did not improve its flowering or fertility. Different temperature regimes did not greatly change the flowering pattern, although S. lycopersicoides and the F1 were more floriferous than the tomato at cool temperature (constant 10o C) and more vegetative at high temperature (30oC) in growth chambers. Different photoperiods were ineffective for inducing flowering. The environmental factor having the most influence on flowering in our tests was light intensity. Standard greenhouse illumination with fluorescent or incandescent lights was of insufficient intensity to stimulate flowering. Best flower production was achieved by growing the plants under very high light intensity, either through the use of mercury vapor lamps or multiple banks of very high output fluorescent tubes. The mercury vapor lamps gave the best results, particularly when used in a cool greenhouse (15o C), but prolonged exposure to mercury vapor lamps caused the plants to become vegetative again after a period of abundant flowering. Limiting the mercury vapor illumination to eight hours daily resulted in more prolonged flowering. The best environmental conditions for flowering as well as production of viable pollen for S. lycopersicoides and the F1 hybrid appear to be 10-15oC and high light intensity (1000-1200 FtC) Philouze, J. The "two leaves between trusses" character in Lycopersicon parviflorum. We used two stocks of L. parviflorum: one lot which we received as L. minutum from I. Pazkowska in Poland, and LA 1321 supplied by C. M. Rick. We studied these two stocks of L. parviflorum under different growing conditions, as well as the F1 hybrids between L. parviflorum and 4 L. esculentum varieties: Moneymaker and Apedice, growth of which is indeterminate (sp+); lines A and B, growth of which is determinate (sp). We counted, in the various lots studied, the number of leaves between successive trusses along the main stem, that is, from the first truss to the eleventh. Results are compiled in the table given below. L. parviflorum has an indeterminate type of growth; in this species the number of leaves which form between successive inflorescences is very regularly two. In Moneymaker sp+ the number of leaves forming between successive inflorescences is very regularly three.  FI hybrids between L. parviflorum and a sp+ variety fall between their parents as regards the number of leaves between inflorescences, this being 2 or 3 (2.5 on an average). In over 90% F1 plants three leaves were found between the first and second truss. Above these no regularity is apparent in leaf number sequence (2 or 3 leaves). F1 hybrids between L. parviflorum and a sp variety have indeterminate growth. They are closely related to their L. parviflorum parent with regards to the number of leaves between successive inflorescences. In most cases, 2 leaves are to be counted between inflorescences, seldom 3 (2.1 on an average). In the course of a genealogical breeding program, we studied the progenies of the Moneymaker x L. parviflorum cross (L. parviflorum stock from Poland). In the F2, there is segregation for the number of leaves between successive inflorescences, average values ranging from 2.10 to 3.10. It seems possible to establish the "two leaves between trusses" character in subsequent generations. f Breeding indeterminate sp+ varieties which regularly form two leaves between successive inflorescences appears worthwhile from the point of view of staked crops, particularly in glasshouses.

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