DE956897C - Breeding of triploid sugar beet seeds - Google Patents

Description

(WiGBl. P. 175)

ISSUED JANUARY 24, 1957

R640p III / 45f

The studies of various breeders in recent years have made it probable that triploid sugar beets with 3 η = 2j chromosomes, which result from the crossing of normal diploid (zn = 18 chromosomes) with tetraploid (4 η - 36 chromosomes), have a higher performance than their diploid and tetraploid parents. In order to be able to economically exploit the power of triploid sugar beets, however, the development of a process for the efficient production of sufficient quantities of triploid sales seeds was necessary. The invention described below provides a solution to this problem.

The production of triploid plants by artificial pollination of diploid plants with the Pollen of tetraploid or tetraploid plants with diploid pollen is not a problem in itself. in the In contrast to diploid plants with 2 »= 18 chromosomes and to teitraploid plants with 47-1 = 36 chromosomes, however, triploid plants cannot be reproduced by seeds. The nature of the Triploidy, the presence of three sets of Chromosomes, in the sugar beet three times nine chromosomes, causes that in the formation The so-called reduction division of the germ cells results in an irregular distribution of the chromosomes takes place, so that germ cells with the most varied of chromosome numbers arise. this leads to once to extensive sterility, but in any case to the fact that triploid sugar beets can be used does not receive triploid seeds again, but seeds with the most varied of unbalanced seeds

Chromosome numbers. In other words, if you want to produce triploid sugar beets, you have to For this purpose, seeds are each time through a process of pollination of diploids by tetraploids or tetraploids can be newly produced by d'iploid sugar beets. A triploid variety cannot be bred will. Artificial pollination between diploid and tetraploid sugar beets is in the Amount that would be required to produce seeds for ίο practical beet cultivation, of course not feasible.

According to the invention, tetraploid or diploid are used to produce triploid sales seeds Used strains that are highly self-sterile. In such strains, the pollen is normal and highly germinable, but for genetic reasons to pollination of its own ovules not or only to a limited extent empowered while fully functional on the so crossing partner is. In the production of the elite seeds for the original triploid seeds seeds of such diploid and tetraploid families are mixed and from this mixed seed Cuttings are raised and brought to bloom together in the second year. One reaps then an almost exclusively triploid seed. The proportion of the individual components to be mixed is selected depending on the degree of self-sterility or self-fertility, the different hereditary rate of development as well as the degree of branching and number of the flowers.

^{For example, a mixture of 50: 50 0} Zo of the two parent forms is used by highly self-sterile parents with the same development speed and the same growth type (branching, number of flowers) and thereby a maximum yield of up to 100% of triploid seeds is achieved.

On the other hand, it is required to be highly self-sterile Combine partners, one of which is little branched and has few flowers is, the other, on the other hand, develops extraordinarily vigorous seed stalks, the mixing ratio must be be changed accordingly in favor of the weaker branched parent.

Must be a diploid (or tetraploid) clan of high self-sterility with a tetraploid (or diploid) clan with low self-sterility are crossed, it is necessary in order to obtain a maximum yield of triploid seeds, the less self-sterile partner according to the degree of its self-sterility to a lower percentage as cross-breeding partner to use.

The proportions of each partner can vary from 30 to 70% depending on the degree of self-sterility and must inductively for each combination before the production of the original (sales seed) to be established. ·

The method according to the invention enables the production of triploid sugar beet seeds with 80 ^fl / o proportion of triploid seeds, preferably 90% and more.

The triploids obtained in this way outperform everyone under comparable conditions existing diploid varieties in the properties important for sugar beet.

Claims (3)

PATENT CLAIMS: i. Breeding of triploid sugar beet seeds, characterized in that by selection Highly self-sterilized tetraploid and diploid strains, the pollen of which is normal and germinable, but genetically not or only to a small degree capable of pollinating one's own ovules are, while they are fully functional with respect to the crossing partner, to common Withdrawn are brought and in this way a seed is produced as a respective sale good that at least 80%, preferably 90% triploid components. 2. A method for carrying out the cultivation according to claim 1, characterized in that the proportions of both parent families that have been brought to bloom together in adaptation be measured according to the genetically determined seed formation ability. 3. The method according to claim 1 and 2, characterized in that the seeds to a high degree self-sterile diploid and tetraploid families mixed, cuttings from this mixed seed and these are brought to bloom together in the second year. © 609 772 I.