Sodium dehydroacetate solutions in concentrations up to 0.8% were found to be effective in reducing discoloration of cut and bruised surfaces of mechanically harvested snapbeans and in reducing some mold and bacterial damage. Techniques for objectively measuring color differences using the Hunterlab Meter D 25 are described.
Three black bean cultivars (Phaseolus vulgaris L.), ‘Midnight’, ‘Black Turtle Soup’, and ‘T-39’, were grown in a sand culture in a series of greenhouse experiments. Seedlings were subjected to various flooding treatments beginning at the time the first true leaves were fully expanded and continuing for up to 14 days. Root systems were partitioned into adventitious, basal, and tap components at harvest. Basal roots accounted for the greatest proportion of the total root biomass in control plants. Adventitious roots became the dominant root component in plants which had been flooded for up to 7 days and then allowed to recover for 7 days. The production of adventitious roots by flooded plants reduced their shoot:root ratios to values closer to those of unflooded control plants. ‘Midnight’ plants usually had larger basal roots and higher total root and shoot weights than plants of the other 2 cultivars. All 3 cultivars, however, were proportionally affected to the same extent by flooding.
Two lines of black bean (Phaseolus vulgaris L.), ‘70001’ and ‘Strain 39’, were grown at between-row spacings of 76, 61, and 46 cm. Cultivation treatments included an uncultivated check and a single cultivation at 1 of 3 plant growth stages: first trifoliolate leaf fully expanded; anthesis; or pod elongation. Root weight, shoot weight, and shoot:root ratio of individual plants decreased linearly as between-row spacing decreased. Biological yield increased linearly as between-row spacing decreased, but seed yield and harvest index did not show significant responses to spacing. None of the measured parameters gave a significant response when the uncultivated control was compared with the average of the 3 time-of-cultivation treatments. Root weight of individual plants and biological yield gave quadratic responses within the 3 time-of-cultivation treatments, both decreasing most markedly with cultivation at the pod elongation stage. Plants of ‘70001’ were larger and lodged less compared to those of ‘Strain 39’. Seed yields of both lines were similar. Results suggest that a single shallow cultivation may be used for black beans grown in narrow rows through anthesis. Although cultivation at the pod elongation stage was generally not detrimental to seed yield, it is not recommended.