Ruderalia sections of the Asteraceae ( van der Hulst et al., 2004 ). Genetic analyses with male fertile diploid and triploid plants indicated that the sterility was inherited cytoplasmically and dominant alleles at two Rf loci could restore fertility
sterility, cytoplasmic male sterility (CMS), or cytoplasmic–genic male sterility in higher plants according to inheritance or origin ( Chen et al., 2017 ). Furthermore, CMS in crop species can be subdivided based on the phenotypic characteristics of the
- and 833-bp amplicons of mitochondrial orf725 ( Kim et al., 2009 ). With these cytoplasmic markers, onion breeders should be able to confidently determine cytoplasms presently in commercial use. Although we did not score male fertility vs. sterility
, hybrid vigor can improve the yield, resistance, and quality of pepper. Cytoplasmic male sterility facilitates the production of hybrid seed. A major concern of hybrid seed production is prevention of self-pollination that can produce seeds that are not
Abstract
The inheritance of male sterility was studied in germplasm of common bean (Phaseolus vulgaris L.) obtained from the Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia. The source was selected for plants with high pollen abortion rates (mean = 91%) and for failure to set any seed or pods by self-pollination when grown in screened greenhouses. These male-sterile plants were crossed with the snap bean ‘Sprite’, and the resulting F1 progenies were all male-sterile under greenhouse conditions. The F1 plants were backcrossed to ‘Sprite’ and the BC1 progenies did not segregate for male-fertile plants under field conditions. Four more backcrosses to ‘Sprite’ have produced progenies that were uniformly male-sterile. It was concluded that the CIAT source of male sterility is inherited through the maternal parent and is cytoplasmic. Nineteen commercial cultivars of snap beans and dry beans were crossed onto BC3 plants, and none of these genotypes restored the pollen fertility in F1 progeny.
Abstract
Several cytoplasmic-genic male-sterile (partially fertile) cultivars were developed in pepper. Three cultivars demonstrated different levels of male sterility; male sterility stability of ‘Bikura’ was reliable for hybrid seed production.
Identification and production of onion male-sterile and maintainer lines by conventional breeding takes between 4 to 8 years, due in part to the biennial nature of onion. In addition, male sterile plants and maintainer genotypes occur at a very low frequency in onion populations (Pike, 1986). A significantly shorter and more efficient alternative involves the screening of breeding lines for cytoplasmic male sterility using PCR-based technology. Thirty short-day onion breeding lines from the Texas A&M onion program were screened for type of cytoplasm (normal or sterile). Specific amplification of a fragment of chloroplast genome was achieved using the polymerase chain reaction according to Havey (1991). Forty-eight individual onion plants were screened per line. Out of thirty lines evaluated, 13 showed 100% sterile cytoplasm, 6 showed 100% normal cytoplasm, and 11 showed both types of cytoplasm. Lines showing normal cytoplasm or both cytoplasmic types were kept and reanalyzed. Only plants presenting normal cytoplasm were grown to maturity to help in the identification of maintainer lines as part of the Texas A&M onion breeding program.
Hybrid leek is more uniform and higher yielding than open-pollinated cultivars and is presently produced by asexual propagation of a genic male-sterile plant. A cheaper method to produce hybrid leek seed would be a system of cytoplasmic-genic male sterility (CMS). Restriction fragment length polymorphisms (RFLPs) in the organellar genomes have correlated with CMS in many crops. We undertook gel-blot analyses of the chloroplast and mitochondrial DNAs to assess cytoplasmic diversity among 62 accessions of the major cultivated forms of Allium ampeloprasum L. (leek, kurrat, and great-headed garlic). No polymorphisms were detected in the chloroplast genome of leek and kurrat. Three accessions of leek and one of kurrat possessed one or two of seven polymorphic mitochondrial probe-enzyme combinations. Great-headed garlic differed from leek and kurrat for six polymorphisms in the chloroplast genome and for many mitochondrial probe-enzyme combinations. Our analyses revealed few organellar polymorphisms among accessions of leek and kurrat, reducing the probability that selection of polymorphic cytoplasms will reveal CMS in leek.
Abstract
F1 plants of Brassica nigra (L) Koch (black mustard) ♀ х B. oleracea L. (broccoli) ♂ were treated with colchicine to produce the amphidiploid (4n) and reduced to the diploid level (2n) by repeated backcrosses with broccoli pollen, thus placing the B. oleracea genome in B. nigra cytoplasm. These progenies after the third backcross were identical with broccoli in appearance but were different in their content of sulfur oils (isothiocyanates) and therefore had a different flavor, cooked or raw. Reciprocal crosses showed maternal inheritance. It is proposed that types developed from this material containing B. nigra cytoplasm be identified by the addition of “n” to the type name, as “broccolin”.
From outcrosses of these early generations by cabbage, two cytoplasmically inherited male sterility systems have been isolated which are expressed only in nigra cytoplasm. A petaloid sterility in which the stamens are transformed to petals or carpels with absence of nectaries is conditioned by a single recessive gene p. Petaloid plants are Npp. Maintainer lines (Opp) for this have been isolated from cabbage and marrow-stem kale.
Vestigial anther sterility (vs) in which the anthers remain rudimentary, does not cause other flower abnormality, including nectary formation, and seed is set freely. Vestigial plants are only tentatively considered as N vs vs because its manner of inheritance is not yet clear. Preliminary evidence suggests that p is epistatic to vs, and that either can be transferred to other stocks.
A highly fertile vigorous B. carinata A. Br. (n=17) amphidiploid was isolated in the second generation.
Abstract
Cytoplasmic male sterility (CMS) has been described in many of our cultivated crops and is commercially useful in the production of hybrids when pollen vectors will provide the necessary economic levels of seed production. In the more common type, the sporophytic, the development of the microspore is affected by the abnormal growth of the tapetum or mistiming of callose formation and, in corn at least, the mitochondrial complex is involved. In the gametophytic system the factor causing abortion of the pollen apparently resides in the microspore rather than in its environment. Other systems which suggest plasmid-like inclusions associated with CMS have been reported. Transfer to the cytosterile mechanism by cell fusion has been accomplished, but wider application of this technique waits on methods for development of plants from naked protoplasts In more species.