Chase Road

Research not done; ideas left over

--Chase, SS

INBREDS FROM MEIOCYTES: As a corn breeder, have you ever seen a super plant and wished you had the inbred lines to reproduce it? I’ll tell you what to do; and you can figure out how. Take a meiocyte, in the male or female line; completely inhibit crossing-over; separate the sister cells of Division I, one from the other keeping both; culture each cell of each pair separately to produce an embryo or set of embryos; grow these to maturity. Each will be a homozygous diploid; each crossed with its mate will reproduce the elite genotype. You can have dozens of complementary pairs of inbreds for each original elite individual or hybrid!

PARTHENOGENESIS: What happens to the extra male sperm in maize parthenogenesis? It does not go to fuse with the polar nuclei and the other sperm nucleus--the endosperm is triploid, not tetraploid. Is it left totally out of the system? I think it likely that it goes to the suspensor. Parthenogenetic rates increase when pollination is delayed. Perhaps the sperm enters the egg after the egg has achieved readiness for division. And the egg divides before syngamy can be effected. This could also account for the fate of the female nucleus in cases of ‘androgenesis’.

DIPLOIDY AND ILLEGITIMATE CROSSING-OVER: In the evolution of control of DNA by the organism, the step that made maize heterosis possible (and also diploidy and higher plants and animals) was prevention of crossing-over of homologous chromosomes at all somatic and mitotic stages of the sporophyte; crossing-over is limited to meiosis. ‘Illegitimate’ crossing-over can occasionally occur. Can it be forced and used as a breeder’s tool? Illegitimate crossing-over leads to chimeral homozgosity.

TEOSINTE AS FOOD PLANT: Teosinte, ancestor of maize, is an unlikely food grain as is. Perhaps the hydroxide treatment of maize grain was invented for application to teosinte grain before maize evolved. Both maize and tortillas originated in Meso-America. Perhaps the tortilla came first.