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Abstract

Effective, inexpensive, disposable pollination aids (bee-sticks) can be made by gluing the thoraxes of dead honey bees (Apis mellifera L.) to the tips of wooden toothpicks. Bee-sticks also are suitable for the short and long term storage and for shipment of pollen.

Open Access

Thirty-seven Brassica rapa L. and B. juncea L. lines from nine subspecies were tested for their reaction to two pathotypes of Fusarium yellows (Fusarium oxysporum Schlecht. f. sp. conglutinans (Wr.) Snyd. & Hans. race 1 and F.o. f. sp. raphani Kend. & Snyd. A subset of 16 lines from these same vegetable types were tested for their reaction to four strains of turnip mosaic virus (TuMV-C1, C2, C3, and C4). Resistance to both Fusarium pathotypes was widespread in these Brassica subspecies, whereas resistance to any strain of TuMV was uncommon. The broad availability of resistance to Fusarium yellows and scarcity of resistance to TuMV necessitate different approaches to obtain disease-resistant cultivars.

Free access

Abstract

Sodium chloride solution applied to the stigma of self-compatible Brassica campestris L. plants induced self seed setting. Maximum seed per set silique occurred on flowers treated 10 to 15 min before self-pollination with 15 g·liter–1 NaCl solution applied either with a micropipette (8.2 seeds/silique) or with a moistened cotton swab (7.2 seeds/silique). The salt treatments were shown to increase pollen adhesion and pollen germination on the stigma and to reduce callose formation on the papillae.

Open Access

Abstract

Forty-six Chinese cabbage [Brassica campestris spp. pekinensis (Lour) Olsson] lines consisting of open-pollinated cultivars, inbreds, and F1 hybrids from China were screened for seedling resistance to downy mildew (Peronospora parasitica) (Pers.) Ex. Fr. Thirty-seven lines of this collection were screened for turnip mosaic resistance. Five lines showed dual resistance to downy mildew and turnip mosaic. Resistance to downy mildew at the cotyledon stage, expressed as a reduction in the sporulation capacity of P. parasitica, was under dominant monogenic control. Turnip mosaic resistance was expressed as a hypersensitive reaction. Genetic analysis of a cross between turnip mosaic resistant and susceptible parents suggested that resistance was conditioned by 2 dominant genes.

Open Access

Abstract

The glucosinolates (GSs) were estimated in the normally eaten portions of 72 cultivars of Oriental brassica vegetables including mustard greens (Brassica juncea L.), Chinese kale (B. oleracea L. Alboglabra Group Bail.), Chinese cabbage (B. rapa L. Pekinensis Group Bail.), pak choy (B. rapa Chinensis Group Bail.), tendergreen (B. rapa Perviridis Group Bail.), turnip (B. rapa L. Rapifera Group Bail., B. narinosa Bail., and B. nipposinica Bail.). Variation in GS profiles was complex. There was variation in percentages of major GSs and total GS among B. juncea, B. oleracea, and the combination B. rapa plus narinosa and nipposinica and among four subspecific groups of rapa plus the two species closely related to rapa: narinosa and nipposinica. B. juncea had distinctively high proportions of allyl-GS, ranging from 81% to 94%, whereas B. oleracea had distinctively high proportions of 4-methylsulfinylbutyl-GS, ranging from 9% to 68%. Differences in GS profiles among the rapa groups, narinosa and nipposinica, were less distinctive. Cultivars of pak choy from China differed in percentages of three minor GSs from cultivars from Japan and elsewhere. There was also variation among cultivars of Chinese kale and between turnip foliage and roots.

Open Access

The short time to flower and rapid production cycle of dwarf Brassica lines make it a promising candidate as an oilseed crop for NASA's Controlled Ecological Life Support Systems (CELSS) program. Breeding lines provided by Paul H. Williams are being screened at Purdue University for productivity and yield rate using soilless culture techniques under controlled-environment conditions. The small, irregularly-shaped Brassica seeds did not respond well to conventional methods of germination above the batch hydroponic systems, even when a variety of capillary ticking materials were used. At best, attaining uniformity of seedling stands required transplants, which compromised potential yield rates in terms of mechanical damage and inhibited seedling establishment. Present emphasis is on solid substrate soilless mixtures using passive ticking hydroponics systems. Crop growth rate, harvest index, and overall yield are being compared as a function of planting densities ranging from 117 to 1423 plants/m2 of growing area. Yield parameters are also being evaluated as a function of growth medium and level of ambient CO2 in the growth chamber atmosphere. Research sponsored by NASA Cooperative agreement NCC 2-100.

Free access

Abstract

Sweet cherries (Prunus avium L.) treated with (2-chloroethyl)phosphonic acid (ethephon) to facilitate harvesting, were low in soluble solids in 1972, but not in 1973. Bruising, pitting and torn stem attachments were attributable to picking method rather than ethephon treatment.

Open Access