paternally transmitted ( Havey, 1997 ; Havey et al., 1998 ). This unique mode of transmission allows for the separation of chloroplast and mitochondrial effects by reciprocal crossing. The cucumber chloroplast DNA is similar to most plants in size and
Abstract
Five selected lines of lentils (Lens esculenta Moench.) were used to determine percentages of natural crossing. First generation seed was classified into S1 and F1 groups after recessive fluorescent yellow cotyledonous maternal flowers were crossed naturally with pollen for dominant red cotyledonous flowers. Natural pollination between lines ranged from 0.01 to 0.08%. No F1 seed was produced on plants inside of wire screened cages although the cages included honeybees, air-borne pollen and maternal and paternal plants having alleles for yellow and red cotyledons, respectively. This indicates that neither honeybees nor air-borne pollen are major factors in natural cross pollinations. Seed yields from caged plants indicate that lentils are highly self-pollinated and need no agent to assist self-pollination.
Abstract
In the paper “Comparison of Two Methods of Hand-crossing Vigna unguiculata (L.) Walp” by K. W. Zary and J. C. Miller, Jr. [HortScience 17(2):246-248. 1982] there is an editing error in the abstract. Crossing method 1 should read “method 2” and method 2 should read “method 1.”
Abstract
Five lines of cowpea were crossed in a complete diallel, using 2 methods. Crossing success rate was greatly enhanced by collecting pollen donor flowers on the morning of anthesis, storing them until late afternoon, and then completing the cross on freshly emasculated flowers (method 1) as compared to utilizing pollen donor flowers for crossing immediately upon collection, early to mid-morning on the day of anthesis (method 2). Significant differences in success rate were found among cultivars used as seed parents in method 2, while no such differences were observed in method 1. Significant differences in success rate were found among cultivars used as pollen parents in both methods.
Little is known about the mechanisms controlling interspecific barriers, unlike the well studied intraspecific barrier, self incompatibility (SI),. A unilateral crossing barrier (unilateral incongruity - UI) exists among the Lycopersicon species, in which crossing is impeded or prevented in one direction. Since both UI and SI can give unilateral differences in seed set, suggestions have been made that UI and SI are functionally related. L. pennellii LA716 is self-compatible, unlike the other accessions which are SI, but LA716 still exhibits UI with L. esculentum (esc). We observed the development of pollen tubes in self and cross pollinations of LA716, esc and SI accessions of L. pennellii (pen). Selfed pollen tubes in esc were at the ovary in 24 hours, while pen were 1/2 way down the style and in LA716 the pollen had not germinated. By 48 hours, the pollen tubes in LA716 were in the ovary and growth had halted in pen styles. Crosses with LA716 pollen on esc and pen resulted in pollen tube growth starting within 24 hours continuing to the ovary. Thus, UI is not a SI response and LA716 shows a delayed pollen germination and growth unlike the other Lycopersicon species examined.
The use of wild species as breeding materials was tried for expanding hereditary variation in strawberry. Some interspecific hybrids setting large fruits with peculiar aroma have been bred by pollination of F. vesca to F. xananassa. Although Asian wild diploid strawberries such as F. nilgerrensis or F. iinumae have not been exploited as a breeding material until the present, the crossing test between cultivated strawberries (8x) and the Asian wild strawberries (2x) were attempted. The interspecific hybrids originated from pollination of F. nilgerrensis or F. iinumae to F. xananassa cv. `Toyonoka' were all sterile pentaploids. By in vitro colchicine treatment of these sterile hybrids for chromosome doubling, many fruiting interspecific hybrids were produced. In particular, some superior hybrids were obtained from `Toyonoka' × F. nilgerrensis. From the results of RAPD analysis, the interspecific hybrids had the fragments specific for both parents. While their morphological characters were close to `Toyonoka', they had some characters from F. nilgerrensis, such as numerous hair on their petioles and peduncles. Their fruits have good characters that are same level of cultivated strawberry about size, Brix, acidity, and vitamin C content. The flesh is soft and skin color is pale pink. The aroma components are resemble F. nilgerrensis, and enrich ethyl acetate. The fragrance of interspecific hybrid like peach is characteristic.
from breeding through selfing. Breeding process. P. villosum ‘V-1’ ( Fig. 1A ), was used as female parent for crossing to P. spicerianum ‘Z-1’ ( Fig. 1B ) in Dec 2013. Immature fruits were collected in Aug 2014. The method of Zeng et al
-flowering hydrangea progenies from crossing Hydrangea chinensis and H . macrophylla cultivars were obtained without ovule/embryo rescue. Origin Cuttings of Hydrangea chinensis were collected from the northern part of Taichung in Taiwan (long. 23°188 N
Abstract
Twenty-four traits in generations 2 to 7 of a randomly intercrossing sweetpotato [(Ipomoea batatas (L.) Lam.] population were studied. Mean changes detected were: increased flowering, reduced leaf whorl purpling, increased vine purpling, decreased vine diam, decreased root wt, fewer smooth skinned types and some increase in vine length. Changes in the fusarium wilt index were not significant but distributional changes were important; fewer plants with high levels of resistance occurred in the later generation. Reductions in vine diam and in root wt were considered independent of each other. There was no indication that the natural selection for increased flowering was responsible for either vine diam or root wt reductions.