ISHS Acta Horticulturae 438: III International Congress on Cactus Pear and Cochineal
DISTRIBUTION OF PHENOTYPIC CHARACTERS WITHIN A SEEDLING POPULATION FROM OPUNTIA FICUS-INDICA (CV “GIALLA”) |
| Authors: | G. Nieddu, I. Chessa |
| Keywords: | Polyembryony, seed germinability, seedlings |
| Abstract:
Genetic improvement in Opuntia needs basic information on useful methodologies related to selection, breeding and seedling growing. In order to acquire knowledge on the level of polyembryony and on the inheritance of important characters related to breeding and systematic studies, trials on seedling culturing have been conducted from 1992 to 1995. A population of about 500 seedlings of different age obtained from mature seeds of Opuntia ficus-indica cv “Gialla”: (72 three-year-old plants, 222 two-year-old and 103 one-year-old) were observed in a collection field. Several tests on germination potential and seed vigour as related to sowing time have been previously carried out. The highest germination rate has been observed in growth chamber, and in open air in July when higher temperature values occurred. A great variability in the percentage of polyembryony has also been observed. Morphological traits related to seedlings growth showed to be normally distributed. Cladodes were in most of the plants ovate shaped. The presence or absence of spines, as well as their amount showed a great variability. Unlike the mother plant, a small percentage of seedlings were very spiny, a few individuals were spineless, while in most of the progeny a different degree of spininess was observed. | |
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