Search Results

You are looking at 1 - 10 of 115 items for :

Clear All
Author:

Abstract

The purpose of this study was to compare the relative fecundity of tetraploid × hexaploid and hexaploid × tetraploid crosses in blueberry. Four types of crosses were made using cultivars and advanced breeding lines consisting largely of V. ashei Reade (6×) and V. corymbosum L. (4×). Fruit set, number of developed seeds per ripe berry, and number of seedlings per pollinated flower were determined. Tetraploid × hexaploid crosses averaged as high in percent fruit set as tetraploid × tetraploid crosses, but seed number per ripe fruit was only 29% as high and seedling number per pollinated flower only 35% as high. Hexaploid × tetraploid crosses, by contrast, set only 48% as much fruit as hexaploid × hexaploid crosses. Despite reduced fruit set, hexaploid × tetraploid crosses averaged almost as high in number of seedlings produced per pollinated flower as the reciprocal cross. In both types of cross, the success rate strongly depended on the particular genotypes used in crossing. The overall success rate from crosses between tetraploid and hexaploid clones was 2.32 seedlings per pollinated flower, which is high enough to allow production of large pentaploid populations for use in breeding.

Open Access

important to consider seed production of a cultivar in the landscape over the course of its reproductive life. Matrix population models show that for long-lived plant species, large changes in fecundity result in relatively small changes to population growth

Free access

maintaining the desirable landscape characteristics. The average number of seedlings per pollinated flower, an overall measure of female fecundity, was reduced from 119.3 for C. radicans to only 0.008 for ‘Chastity’, a reduction in fertility of 99

Free access

.M. Lubell, J.D. 2012 Fecundity of Japanese barberry ( Berberis thunbergii ) cultivars and their ability to invade a deciduous woodland Invasive Plant Sci. Manag. 5 464 476 https://doi.org/10.1614/IPSM-D-12-00029.1 Caruso, I. Castaldi, L. Caruso

Open Access

The influence of cryogenic pollen storage on fruit set and seed production in tomato (Lycopersicon esculentum Mill.) was investigated. Flowers pollinated with pollen samples stored for 5 weeks at –80C, with or without 20 h precooling at 4C, had similar fruit set and number of viable seed per fruit as those pollinated with fresh pollen. Pollen samples, which were repeatedly cooled (–80C) and warmed (to 22 to 24C) for up to six cycles, continuously maintained the same viability as the fresh pollen. When cryogenically stored pollen of L. esculentum 2-837, LA359, LA3198, and LA3199 were used to pollinate LA359, the number of viable seed formed per fruit differed significantly. Results of this study suggest that pollen cryopreservation can be used successfully for tomato breeding and germplasm storage.

Free access

Mean seed production in tetraploid × diploid crosses of Salpiglossis sinuata R et P. was similar to that in diploid × diploid crosses, but germination of the resultant triploid seeds was low (8%). Parental line selection resulted in some germination improvement. Triploid hybrids from these crosses were vigorous, with floral characteristics resembling tetraploids. The fertility indices of self-pollinations of triploids and pollinations by diploid and tetraploid plants were <1, 22, and 6, respectively, compared with 176 for diploid × diploid crosses. Thus, the self-pollinated triploids were virtually sterile.

Free access

Abstract

Nymphs of Aphis gossypii Glover (Western Biotype) reared on bitter plants of ‘Tablegreen 65’ and ‘Marketmore 70’ cucumber required less time to reach maturity and produced more generations in 184 days than those reared on non-bitter plants. The greatest number of nymphs per adult aphid was produced by aphids on 8-week-old non-bitter plants of ‘Tablegreen 65’. Non-bitter plants of both cultivars supported a significantly greater aphid population density after 30 days than bitter plants.

Tests of aphids in greenhouse cages indicated no significant differences in damage caused by melon aphids to bitter and non-bitter plants of ‘Tablegreen 65’ and ‘Marketmore 70’.

Open Access

fecundity, age-stage specific life expectancy, and population growth parameters ( Chi et al. 2020 ). Life table study is a fundamental ecological and biological tool that provides insight into the population dynamics of the arthropods of interest ( Chi 1988

Open Access

found to reduce the survival and fecundity of several aphid species ( Brevicoryne brassicae , Myzus persicae , Aphis nerii , Aphis pomi , Aphis fabae , Acyrthosiphon pisum ) ( Dreyer et al., 1984 ; Honeyborne, 1969 ; Smith, 1969 ; Tahori et al

Free access

, the study clearly demonstrated a suppression of liverwort asexual fecundity ( Figs. 8 and 9 ). Ozone treatments reduced the number and size of the gemmae ( Figs. 8A, D–F and 9 ), and although some viable gemmae were observed under the highest

Free access