Influencing of the cytoplasmic male sterility and fertility in beets

Abstract

Attempts have been made to find a method to control the male sterility-male fertility balance in beets. It proved not possible to induce male sterility in O-types by means of grafting. Nor was transmission by infection with aphids or by rubbing with juice successful.In some cases exposure of germinated seed of plasmatic male sterile annual beet material to temperatures of up to 55°C resulted in the occurrence of male fertile plants. The accompanying change could not be uniformly explained from the propagation obtained. It is possible that S-plasm has changed into N-plasm. Further investigations are in progress. | NTRODUCTIONIn 1945 OWEN gave a genetical explanation for the occurrence of a certain tbrm of male sterility in beets. He could explain his observations by means of two plasmic forms, S standing for male sterility (ms), N for normal flowering, and by two chromosome genes X and Z. The genetic structure Sxxzz causes full ms and can be maintained by pollinating with the form Nxxzz (= O-type), which normally flowers.OwEN observed abnormalities in his material for which he could not account even with the aid of this simple scheme. Only occasionally did an ms plant produce a fertile branch while external circumstances often influenced the expression of ms. ROHR-BACH (1965, III) is of the opinion that this influence is governed by genes. It was also in Epilobium that JONES and GAaELMAN (1965) discovered a normal fertile subclone produced by a cytoplasmic-sterile clone.Carrying out investigations, BLISS and GABEL (1965) found that the X-gene is the determining factor regarding ms florescence and the Z-gene (hypostatically to X) is responsible for the characteristic semi ms. ROHRBACH also concluded (1965, II) that the X-gene and the Z-gene differ in action and that the forms of S-plasm may differ as well.Ms plants and matching O-types have been found in various beet varieties and the practical breeder has been able to manage with OWEN'S scheme. Using ms material numerous hybrid varieties have been introduced into commerce over the years. It is true, that it is possible to recognize ms plants by the inflorescence but O-types (nonrestorers) have to be traced by means of test crossing. This time-consuming procedure has to be repeated to check genetic purity. It would facilitate the maintenance of the ms material if one could control the balance sterile-fertile so as to be able to dispense with the O-types or to develop them from ms-material by means of some prompt interference. A 2.3-dichlorosisobutyrate induction of male sterility (Wla-, 1960) also en-23

CYTOPLASMIC MALE STERILITY AND VIRUS INFECTION IN <i>CAPSICUM ANNUUM</i> L.

“…The evidence obtained from grafting experiments between cytoplasmic male steriles and their normal (fertile) counterparts (maintainer) does not support the concept of virus control (Atanasoff 1964) of cytoplasmic male sterility in Beta (Cleij 1967), Capsicum (Ohta 1961b), Nicotiana (Sand 1960), Tyiticum (Lacadena 1967;Zeven 1967), and Zea (Shumway and Bauman 1966). In the case of Capsicum grafting was made between Fresno Chile ((N) rf rf) and S-Fresno Chile ((S) rf rf) , the material which has never recovered pollen fertility by thermoshock treatments (Ohta 1968a, b).…”

“…Sterilization experiments do not support the viral nature of a cytoplasmic entity in Zea (Shumway and Bauman 1966), Tyiticum (Zeven 1967), and Capsicum (Ohta 1968a, b). Again, on the other hand, the viral nature of a cytoplasmic entity in Beta is suggested from Cleij's experiments (Cleij 1967). One may speculate, however, that the involved entity had originated from an exogeneous virus in the course of evolution followed by the loss of infectivity.…”

Factors Influencing Petaloidy Expression in the Carrot, Daucus carota L.1

“…Transmission of cytoplasmic male sterility through a graft union has been reported in petunia (3,10,15,16) and sugar beets (9), although transmission was not ob- tained by all workers (6,14). Only negative results were obtained in tobacco (25), peppers (21), corn (28), and Crotalaria mucronata (11).…”

The Viral Nature of Cytoplasmic Male Sterility in Plants

“…4. CLEIJ (1967) grafted male sterile stocks of sugar beets 'SL9460' with scions of the matdiing fertile 0-type, but also got negative results. He also exposed germinated seeds of cytoplasmic male sterile sugar beet to temperatures of up to 55'C for 10 to 60 minutes, which gave some fertile plants, but he concluded: "The accompanying change could not be uniformly explained from the propagation obtained.…”