No abstract

Nondestructive estimates of fruit volume are used for yield prediction. They are also used to study the relationship between fruit expansion rate and susceptibility to diseases or physiological disorders such as fruit cracking. A model relating bell pepper (Capsicum annuum) fruit diameter and length to its volume was derived using the equation of the volume of a sphere as the starting point. The model has the following formula: VF = KD2 Lπ/6, where VF is fruit volume, K is the shape factor that varies with fruit type, D is fruit diameter, and L is fruit length. The model is simple, easy to use in the field, and may account for variations in fruit shape. Regression analyses using actual fruit volume of bell pepper measured with the water displacement method and the volume estimated using different equations showed that accuracy of the new model is comparable to that of one of the best models previously proposed. However, because the model is less complex than previous models, it is easier to use in the field.

GOLDY, R. G., and P. M. LYRENE. 1984. Meiotic abnormalities of Vac.c.inium czshei x Vncac-inium dnrrowi hybrids. Can. J.Genet. Cytol. 26: 146-151. Meiosis was studied in pollen mother cells of three Vncc-inium nshei (2n = 6.u = 72) x Vncc.inium dtrrrowi ( 2 n = 2x = 24) hybrids. Numerous irregularities were found, including 60 somatic chromosomes instead of the expected 48, two synezetic knots, two nucleolar organizing regions, lagging chromosomes at anaphase 1 and 11, nonassociating chromosomes, meiotic asynchrony, micronuclei at telophase I and 11, misaligned spindles, extra nucleoli. increased percentage of unreduced gametes, incomplete tetrads, and polyspory. Lagging chromosomes at anaphase 1 did not appear as univalents, but as bivalents. This suggests a base chromosome number for Vaccinium of x = 6, not x = 12.

Field studies were conducted in 2003 and 2004 to determine effects of withholding irrigation on pepper (Capsicum annuum) plant height, leaf chlorophyll content, yield, and irrigation water use efficiency. Irrigation treatments were initiated at pepper transplanting (S0), after transplant establishment (S1), at first flower (S2), at first fruit (S3), or at fruit ripening (S4). The control treatment received only enough water to apply fertigation (FT). Withholding irrigation did not affect pepper plant height except FT treatment, but increased leaf chlorophyll content. Withholding irrigation until S4 saved 50% and 41% of irrigation water in 2003 and 2004, respectively, without affecting fruit yield compared with the treatment where irrigation started at transplanting. However, yield in the FT treatment was significantly reduced. Irrigation water use efficiency (pepper yield per unit area per millimeter of water applied) was maximum at S4 (59.1 kg·ha−1 per millimeter) and S3 (24.1 kg·ha−1 per millimeter) in 2003 and 2004, respectively. Similar trends in response of pepper to the irrigation treatments were observed in 2003 and 2004 even though there were large differences in rainfall, and pepper yield between years. This suggests that withholding irrigation until first fruit may help to maintain pepper yield while reducing irrigation costs. However, it is important to have adequate soil moisture at transplanting to insure adequate transplant establishment.

Six Vitis rotundifolia Michx . (muscadine) grape genotypes were measured to determine variation and simple correlations between flower and fruit number/cluster, fruit cluster and individual fruit weight, fruit set and total vine yield . Significant variation was found for each trait, except fruit cluster weight . Range in mean values across selections for each trait were : 72 to 202 flowers/cluster ; 16 to 26 fruit/cluster ; 88 .1 to 112 .2 g/fruit cluster ; 3 .4 to 7 .2 g/fruit ; 11 .3 to 23 .4% fruit set ; and 21 .0 to 71 .0 kg/vine for yield . Simple correlation values ranged from r = 0 .05 for flower number to cluster number to r = 0 .69 for fruit number to cluster weight . No trait was highly correlated to total yield . Therefore, to increase yield in muscadines it appears best to select for total yield and not for components contributing to yield .