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Dermot P. Coyne

Abstract

Mosaic-like crinkled-leaved variegated rogues were found in the ‘Stringless Green Refugee’ snap bean variety. Grafting experiments suggested that this condition was not due to an infectious virus. The degree of expression of the symptoms was influenced by temperature and the symptoms appeared almost completely masked at 80°F. This suggests that effective selection against the rogue should be done in cool climates. Differences in the expression of the character was observed between field and greenhouse grown plants.

Segregation in the F2 ‘G.N. 1140’ X variegated rogue indicated that this character was controlled by a major gene with variegation being recessive. In reciprocal crosses between 2 ‘Bush Blue Lake’ lines X variegated rogue, almost complete elimination of the variegated plants was noted in segregating generations. The similarity of some of these results to serotype mechanisms and/or virus tolerance is discussed.

Open access

Dermot P. Coyne

Abstract

Segregation in squash (Cucurbita moschata Poir.) crosses between a ‘Crookneck Butternut’ selection (green-leaf) × ‘Golden Cushaw’ (mottle-leaf) and ‘New Hampshire Butternut’ (green-leaf) × ‘Hercules’ (mottle-leaf) indicated that the mottle-leaf trait was primarily controlled by an incompletely dominant gene (M).

Open access

Dermot P. Coyne

Abstract

Abnormal elongation of styles of tomato flowers in hot dry weather has been observed by some workers (5, 6, 7). This has been found to cause poor pollination and reduction in fruit set. The exposed stigmas may also dry up in hot dry weather resulting in failure of fertilization and blossom drop (57). Tomato styles were also observed to elongate abnormally under conditions of low soil moisture (5). A differential response of style elongation to length of photoperiod for 2 greenhouse tomato varieties was observed by Burk (1). Howlett (2) reported that the maximum length of pistil in relation to the stamens was obtained when the plants were growing during a period of relativelv short day, under light of low intensity, and with an abundance of readily available nitrogen. The author has found no reports on the differential response of style elongation of tomato varieties grown under different soil moisture levels.

Open access

Dermot P. Coyne

Abstract

The effect of CCC, B-9 and Gibberellin A-7 on time of flowering and the node of the first flower of the short-day Great Northern Nebraska No. 1 sel. 27 dry bean line under short and long photoperiods was investigated in the greenhouse. CCC was the only chemical which promoted early flowering under long photoperiods. Under long photoperiods, B-9 caused the first flower to open at higher nodes. The possible usefulness of these findings is discussed.

Open access

Dermot P. Coyne

Abstract

Ethrel, 250 ppm, applied at 9 weekly intervals, starting when the first true leaf was about 1 inch in diam. produced 91% pistillate flowers, increased fruit numbers, and decreased fruit wt of ‘New Hampshire Butternut’ squash. Plant spread was reduced under this treatment due to a shortening of in tern ode length. Treatments of 0, 50, 100, 250, and 500 ppm of Ethrel applied once did not change significantly the no. of pistillate flowers on a whole plant basis. The total fruit yield did not differ among treatments. Ethrel could be used to develop a female line of ‘New Hampshire Butternut’ as an aid in the development of F1 hybrids having low crookneck frequency.

Open access

Dermot P. Coyne

Abstract

In growth chambers at 26°±2°C (day) and 21°±2° (night), a 15 hour photoperiod delayed flowering on ‘Great Northern (GN) Nebraska #1 sel. 27’ by 47 days and in Plant Introduction (PI) 207262 by 48 days over a 10 hour photoperiod. The cultivars ‘GN 1140’ and ‘GN Nebraska #1’ and a near-isogenic determinate ‘GN Nebraska #1’ flowered at the same time under both photoperiods. Both near-isogenic lines, determinate and the early flowering ‘GN Nebraska #1 sel. 27’ flowered earlier than ‘GN Nebraska #1 sel. 27’ in all field experiments. The near-isogenic determinate ‘GN Nebraska #1’ flowered earlier than the ‘GN Nebraska #1 cultivar in 2 out of 3 field experiments. The delay in flowering of ‘GN Nebraska #1 sel. 27’ was much greater at higher night temperatures at Lincoln than under lower temperatures at Scottsbluff when the photoperiod was the same. Delayed flowering of PI 207262 under long photoperiod was controlled by a single recessive gene.

Open access

Dermot P. Coyne

Abstract

Bowen (1988) reported that the first large scale production of dry edible beans in the United States started in Orleans County, N.Y., in 1839. Later, the crop spread to many other areas in the midwestern Great Lake states and finally to many western states as the country developed. The United States became one of the most productive and efficient producers of dry beans in the world in this century. The following states, in ranked order, had the most area planted to the dry bean crop in 1986: Michigan, North Dakota, Nebraska, Colorado, California, and Idaho (Table 1). Average yields in the United States reached 1509 kg-ha-1, while yields in Brazil and Mexico, which produce 78% of South America’s dry beans, were 500 and 578 kg·ha-1, respectively, during 1977–1979 (CIAT, 1981). Brazil is the largest producer of dry beans in the world (2,222,0001) (CIAT, 1981), while the United States produced ≍968,000 (5-year average, 1982 to 1986) (Table 2). The differences in yields between the two regions is that, in South America, beans are generally produced on small farms on infertile soils with limited inputs and using landraces in association with other crops (CIAT, 1981). Beans in the United States are generally grown in monoculture on large farms on fertile soils using productive cultivars and generally under high management inputs.

Open access

Dermot P. Coyne

Abstract

Horticulturists can contribute significantly, in association with other professions, to the alleviation of the most poignant human stresses of our age, namely, poverty, hunger, malnutrition, and the social unrest and diseases which they engender in the least developed countries (LDCs). These stresses are accentuated by escalating populations which need to be addressed by others. The problems haunt our souls and challenge our intellect for solutions. Millions afflicted by famine cry out desperately and repeatedly for aid on our television screens; nowhere was this more evident than in Africa in 1985. Millions more, in silence and in oblivion, live anguished lives of abject poverty and misery.

Open access

Dermot P. Coyne

Abstract

Butternut squash (Cucurbita moschata Duch ex Poir.) is one of the most popular types of winter squash grown in the United States. Most Butternut squash is unstable for fruit shape and mutation to crookneck fruit occurs at a high frequency. Seed stocks need to be rogued frequently in order to keep the no. of crookneck and dimorphic plants at a low level. Two cultivars, small fruited ‘New Hampshire Butternut’ (NHBN) and large fruited ‘Waltham Butternut’, stable for fruit shape have been introduced. The fruit of the former cultivar is considered to be too small for general use. ‘Waltham Butternut’ has attractive fruit shape and high yield, but is considered to have a different flavor and texture than older butternut cultivars. The purpose of my breeding program was to develop a medium size butternut squash free of the crookneck rogue and with a flavor and texture similar to ‘Butternut 23’ (Asgrow Seed Co.).