Individual Plant Data Research Articles

Computer Analysis of Individual Plant Data from Genetics Experiments

ABSTRACT A computer solution to some of the methods of Mather, Allard, Castle-Wright, Powers, and logical extensions is described to reduce partially data from individual plants of the P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 , generations where quantitative or semi-quantitative character measures are involved. After deriving phenotypic variances, genetic variances, heritability, minimum factor number, and scale tests, an attempt is made to fit the data to a 1 locus hypothesis with indicated dominance, and to a 2 loci hypothesis with varying linkage, relative gene value, dominance, and parental genotypes. The algorithms and the genetical assumptions are given.

EARLY-GENERATION TESTING FOR FRUIT MATURITY AND SIZE IN TOMATO CROSSES

Individual F2 tomato plant data in a scatter diagram were used to select segregants for early maturity combined with large fruit size. Selections which were tested in the F3 in replicated and progeny-row tests were carried through to a comparative test in the F5. The relationship of fruit maturity and fruit size in the F2 and F3 indicated that F3 replicated tests using individual plant data are of considerable value in the early selection of superior lines. The F3 performance also provided an indication of the performance of subsequent generations thus permitting immediate decision as to further crossing selfing. The progeny-row test was not sufficiently critical to maintain high selection standards or to provide a reliable indication of the performance of subsequent progenies.

Greenhouse Technique for Evaluating Sweetclover Weevils’ Preference for Seedling Sweetclover Plants1

A method for evaluating preference of adult sweetclover weevils ( sitona cylindricollis Fahr.) for seedling sweetclover plants is discussed. Seedling plants of a homozygous weevil-susceptible selection of Melilotus alba were subjected to the feeding of various numbers of adult weevils. Replicated tests were made with 1, 2, 4, and 6 weevils per plant. Statistical analyses run on the individual plant data showed significant differences between rows of plants. When assumed varieties were randomized so that each appeared the same number of times in each row, no significant differences were noted. Five varieties per flat replicated in two 5 × 5 Latin squares infested with two weevils per plant produced the most reliable results. The use of a homozygous susceptible standard check will provide, for flat to flat, and year to year, comparisons of materials tested.