New mutants.

Rick, C. M.

The following four monogenic mutants appeared spontaneously in fields of standard varieties or varios breeding stocks. All have normal viability and good fertility for genetic tests. Linkage and trisomic tests with them are in progress, but no locations have yet been obtained.

bl - blind (LA59) (breeding stock). Acquired from Dr. P. G. Smith. Growth of axis terminates in single flower or inflorescence as if an extreme expression of sp, yet is independent of the latter. No buds in axils of leaves or cotyledons. Growth may terminate with appearance of the single inflorescence, or in the late season many adventitious shoots may emerge from the midribs. Growth of these new shoots is likewise severely restricted. F2 seg. 226^+ : 77bl. Classification in the most genotypes is good, but in certain combinations expression is less extreme.

gq - grotesque (2-181) (San Marzano). Fruits always abnormal in shape, expression highly variable, usually asymetrical. Fruits may be twisted, elongated, ridged, or even split into two or more lobes. Locule number is usually increased by partial or complete separation of additional carpels. It can often be classified in the flower by the deformity of pistils and moderate distortion of androecia. Discovered on two separate occasions as unfruitful plants. F2 seg. 452+ : 136gq. Classification good.

Nr - Never ripe (LA162) (Pearson). Fruits turn color at normal time, but develop ripe pigmentation slowly, finally attaining a variable dirty orange exterior color and a yellowish red interior color. A normal red color is never developed no matter how long the fruits are retained on the plant or held in storage. Fruits also retain the texture and low sugar content characteristic of normal tomatoes in late green stage. Discovered by Dr. L. L. Morris as a chimeral fruit, part of the tissue of which was Nr/+. Appears superficially as a complete dominant. F2 seg. 270Nr : 113+, the excess of + being significant at the 5% level. Classification good.

sd - sun dwarf (LA15) (breeding stock). Appeared in cultures of G. C. Hanna. Of special interest is the complete dependence of sd upon the environment for its expression. Throughout the late fall, winter, and early spring, growth is entirely normal. The following phenotype is exhibited by sd/sd during the rest of the year, reaching its greatest extreme in early and midsummer. Exposed stems greatly stunted, internodes often being less than 1 cm in length. Stems somewhat constricted above the nodes, showing here a brownish discoloration at first, scar tissue later. New shoots from base of plant grow normally until they break through the chick canopy of foliage. Net effect on whole plant is general stunting and extremely compact growth. All exploratory tests to date indicate that expression of sd is limited by intensity of light within the range of the visible spectrum. Additive and subtractive tests with UV and infrared seem to have no effect. Normal fertility and fruitfulness. Heterozygote intermediate but sometimes difficult to distinguish from+, sd thus being best managed as a recessive. F2 seg. 251+ : 95 sd. Classification good in the proper environment.