Young, P. A.
Five natural chlorophyll-deficient plants were found among nearly 400,000 tomato plants at the Tomato Disease Laboratory at Jacksonville, Texas in 1936 to 1958. Three of these were reported (TGC 4:19). Two similar ones are reported here.
One plant of Selection S1783Y tomato had a branch with normal green leaves and 2 branches with partly albino leaflets. Some of these leaflets were entirely white or yellow while others exhibited large yellow, white or gray sectors or parts of borders. Many upper leaflets became wrinkled and rolled. Seeds from fruits on branches with partly albino leaflets (G2026) produced 150 seedlings. All of them had white to light yellow cotyledons and bright purple stems, and these plants died within 5 to 8 days.
One plant of Homestead tomato had normal branches and branches with partly albino leaflets like those of S1783Y. Its seeds are to be tested for albinism.
Second generation seeds of GR1931B tomato (parent seeds had been treated with thermal neutrons for 4 hours) produced 123 plants of which 2 seedlings had yellow cotyledons and stems while 6 seedlings had white to purple cotyledons and stems. These 8 completely albino seedlings died within 5 to 10 days (TGC 8:39).
These mutant seedlings gave the first chance to distinguish between two kinds of albinism. One kind of seedling was yellow while the other kind was white to purple. Lack of chlorophyll made both kinds lethal. The yellow seedlings resembled those from a radium-induced mutation with the ys-allele, but there is no apparent method of proving their identity (TGC 4:4-8). It may be that these lethals are due to chromosome deficiencies instead of gene mutations.
A different kind of chlorophyll deficiency appeared in the R3-generation of GR1937 tomato from seeds treated with 32,000 r. of gamma rays. The parent plant looked normal. After the R3-plants (GR1937M) were about 6 weeks old, they developed yellowish-green top leaves that distinguished them during the remainder of the growing season. Nearly all of these plants remained fruitless. They were like a few selections in the R2-generation (TGC 8:40). The partial deficiency of chlorophyll was associated with fruitlessness with or without dwarfing.