High tolerance limits for 2S•2S chromosomes reported here were found after crossing a 2n+3(2S•2S) plant with a ditertiary tetrasomic, 2n+2(5L•7S), described by Gill (Genetics 77:61-70; 1974). This cross originated a plant with four extra chromosomes of constitution 2n+3(2S•2S) +1(5L•7S). Selfed progeny of this individual produced two 2n+4(2S•2S) plants. From three generations of selfing on these plants, selection for individuals with higher 2S•2S chromosome numbers made it possible to obtain plants with up to eight 2S•2S chromosomes. Since the original parental plants were of different genetic background (VF36 and San Marzano cultivars), the variability produced in the selfed generations expedited the selection response for tolerant genotypes for higher chromosome numbers. The high tolerance of heterochromatic 2S•2S chromosomes suggests the use of the tomato as an ideal organism for investigating certain aspects of molecular cytogenetics. One extra 2S•2S chromosome adds two nucleolar organizer regions. Hence, it is possible to have plants ranging from two to 18 [2n+8(2S•2S)] nucleolar organizer regions. The versatility of the 2S•2S chromosome system could prove advantageous in elucidating problems concerning nucleolar organization, ribosomal gene regulation, and other related phenomena. Reeves, A. F. Elevated stomata of h. The  hairless  mutant,  h,  located  on chromosome 10, has been used   extensively for several years. It has been described as lacking the larger stem hairs. A close microscopic examination of its stems revealed that the multicellular bases of the large hairs are still present in approximately the normal frequency. Furthermore, at the apex of the multicellular base is found not the typical long trichome, but a fully developed stomatal apparatus. A paper reporting this discovery and including photomicrographs is in preparation. In my present position I will not be able to pursue this further.  I hope someone with the appropriate facilities will take an interes in following up on this developmental abnormality. Scanning EM pictures would be most helpful. Quite by accident in the spring of 1975 some Red Cherry seedlings were induced to develop entire leaves. Just as the seedlings   Reeves, A. F. Phenocopy of e, entire leaf. were emerging through the soil, the greenhouse in which they were growing was fumigated with pyrethrins in the form of a commercial product known as "Fog-a- Sect". Some extremely cold weather immediately following the fumigation prevented opening and airing out the greenhouse for a period of two to three weeks. During this time 100% of the Red Cherry seedlings (ca. 300) produced entire leaves. The phenocopy was so good that I was about to discard the flat, thinking I had planted the wrong seed; however, when the fourth and fifth true leaves developed (and subsequent leaves), it could be seen that these were indeed the normal Red Cherry seedlings. Some of these plants were transplanted to the field where they flourished normally and produced normal fruits. The greenhouse fumigated with one can of "Fog-a-Sect" designed to cover 10,000 cubic feed encompassed about 2,500 cubic feet. Thus, while I do not know the actual concentration of pyrethrins, especially over the extended period of time, it was much greater than that recommended for white fly treatment.

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