Seed survival after very early harvesting
--Major M. Goodman, Sheila D. Goodman and Dianne Beattie

During the summer of 1994, one of our isozyme transplants (7451-3) was injured by earworm or armyworm so that the tassel was destroyed. The plant was a rare favorable recombinant between Sad1 and Glu1 on chromosome 10, so it was used as a female. The top ear developed slowly, so three pollinations were made within 2 days on ears 2, 3, and 4, which silked virtually simultaneously. Ear 1 was left covered with a shoot bag. One or 2 days later, when ear #1 did silk, a pollination was set up to repeat the most important pollination (this particular one had already been made twice). After collecting pollen from 7481-6 (for the third time), it was obvious that 7451-3 was rapidly dying (from the base to the top of the plant) from an Erwinia bacterial stalk rot from irrigation water, and there was no point in making a fourth pollination on a dying plant. Knowing that the three possibly successful pollinations had been made for only a few days, it seemed impossible to salvage them, since we were approaching peak pollination period, and there was no time to arrange for embryo culture. In a half-hearted attempt to rescue something, the three pollinated earshoots were cut off at their points of attachment to the stalk and carried home that night. There they were trimmed a bit at the base, placed in small jars of water (with a bit of sugar added to each jar), and placed under a cool-white fluorescent light (used during the winter season for houseplants). The "developing" ears themselves were not immersed, but the stems were well covered with water. The water/sugar solution was changed several times as it became discolored, and the earshanks were trimmed a bit further. After the husks covering the ears acquired mold, the ears were husked. Ear #3 had rotted and was discarded. The naked ears, #2 and #4 (still greenish and damp) were left to dry under the lights. Ear #2 (7451-3 x 7481-6) had only 11 kernels; ear #4 (7451-3 x 7441-4) had only 3. All of these seeds were subsequently "planted" in the isozyme lab in September, using standard protocols (treated with Thiram 50 WP, wrapped in germination paper, dampened, placed in plastic boxes, incubated for 6 days at 35 C), except that the seeds were additionally surface sterilized in 3% H2O2 for 5 minutes before "planting." After clipping off bits of the coleoptiles, the seedlings were transplanted to 3-inch square peat pots, taken first to the greenhouse, then trucked to Homestead, Florida and transplanted there. All seeds and plants survived. Plant growth was normal. In emergency situations, it may sometimes be possible to salvage even less than seven-day-old kernels with crude and easily arranged methods.
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