Southern pea (cowpea) plants reacted with 4 types of response to southern bean mosaic virus-cowpea strain: 1) susceptible, 2) hypersensitive, 3) hypersensitive plus systemic necrosis, and 4) symptomless reaction. The hypersensitive reaction (resistant) on inoculated leaves was dominant and inheritance was controlled by a single gene pair. In segregating populations of some crosses, systemic necrosis followed the initial hypersensitivity. Although the inheritance of the systemic necrosis was not determined, it appeared to be influenced by temperature. Plants without systemic necrosis were selected from F3 populations.
A mutant trait discovered in a planting of ‘Knuckle Purple Hull’ cowpea [Vigna unguiculata (L.) Walk.] is characterized by proliferated leaf buds, by narrow, elongated, distorted leaflets with irregular margins and abnormal vein curvature, and by sterility caused by failure of the style to elongate. In most flowers, the stigma remained enclosed by the united stamens. Inheritance of this trait is governed by a single recessive gene for which the symbol pbs, for proliferated buds, is proposed.
‘Woodroof’ pecan [Carya illinoensis (Wang) K. Koch] has been released to provide a disease-resistant, very good quality cultivar for home orchards in the southeastern United States where scab [Fusicladium effusum (Wint.)] is a major disease. Within the past 20 years, scab has greatly reduced pecan yields in home plantings in the southeast where the small number of trees does not justify expensive disease-control equipment (3, 5).
The College of Agriculture of the Univ. of Georgia releases 3 cowpea (Vigna unguiculata (L.) Walp.) cultivars which are resistant to blackeye cowpea mosaic virus (B1CMV): ‘Pinkeye Purple Hull-BVR’, ‘White Acre-BVR’, and ‘Corona’. B1CMV causes the most important disease of cowpea in Georgia (3), and it has been found in Alabama (3), South Carolina (3), and Texas (G.L. Philley, personal communication). Infection of cowpea with B1CMV causes significant losses. More important, however, is the synergistic disease reaction (cowpea stunt) which occurs with mixed infections of B1CMV and cucumber mosaic virus (CMV) (4). These 3 cultivars should be useful for commercial production and home gardens, and as parents for breeding programs.
Commercial kiwifruit production often requires substantial inputs for successful pollination. Determining the length of time that female flowers can be successfully pollinated can aid management decisions concerning pollination enhancement. The purpose of this research was to determine the effective pollination period (EPP) for ‘AU Golden Sunshine’ and ‘AU Fitzgerald’. Either 30 (2013) or 32 (2014, 2015) flowers of ‘AU Golden Sunshine’ were hand pollinated each day for 1 to 5 (2013) days after anthesis (DAA) or 1 to 7 DAA (2014, 2015), and then isolated to prevent open pollination. Anthesis was considered the day the flower opened. Similarly, ‘AU Fitzgerald’ flowers were pollinated and then isolated 1 to 6 DAA in 2013 and 1 to 7 DAA in 2015. For ‘AU Golden Sunshine’ in 2013, fruit set was consistent over the 5-day period, but fruit weight, fruit size index, and seed number decreased between 1 and 3 and 4 and 5 DAA. In 2014, fruit set decreased between 1 and 6 and 7 DAA, whereas fruit weight, fruit size index, and seed number each decreased in a linear trend. In 2015, fruit set also decreased between 1 and 6 and 7 DAA, whereas all other responses decreased linearly. Based on fruit set in 2014 and 2015, the EPP for ‘AU Golden Sunshine’ was 6 DAA. The EPP for ‘AU Fitzgerald’, however, was more variable. In 2013, fruit weight, fruit size index and seed number decreased between 1 and 4 and 5 and 6 DAA, suggesting that the EPP was 4 DAA. In 2015, fruit set remained consistent over the 7-day period with fruit weight, fruit size index, and seed number decreasing linearly. Differences in temperature and the alternate bearing tendency of kiwifruit species likely contributed to the discrepancies between the years for the EPP. For each cultivar, reductions in fruit weight, size, and seed number were observed before an observed decrease in fruit set. Greater fruit weight, size, and seed number were observed when flowers were pollinated within the first few DAA, with results varying thereafter.