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  • Author or Editor: W. Haglund x
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Abstract

Single plant progeny (SPP) lines of peas (Pisum sativum L.) selected from the cultivars Early Frosty and Darkskin Perfection were compared for days to bloom, nodes to first flower, and yield. In 1980, SPP lines from within a cultivar deviated significantly in bloom date, nodes to first flower, and yield. One SPP line from each cultivar was compared to the commercial cultivar for yield from 1980 through 1985. The average yield during 5 years for ‘Early Frosty’ and ‘Darkskin Perfection’ was 4.07 and 3.72 t·ha-1 and 5.86 and 5.80 t·ha-1 for their respective SPP lines, equivalent to 44% and 56% yield improvement for the SPP lines. The data obtained from the SPP lines establish that genetic diversity existed within the two cultivars studied. This diversity could be stabilized in SPP lines. With one exception, variation between the SPP lines and/or the cultivar were within the phenotypic descriptions of the original cultivars. The superior yield of the SPP lines selected from ‘Early Frosty’ and ‘Darkskin Perfection’ could not be attributed to the selection of an unknown cultivar contaminating ‘Early Frosty’ and ‘Darkskin Perfection’.

Open Access

Abstract

Growth of seedlings of apple (Malus sp.) and pear (Pyrus sp.) was significantly greater in 14 out of 19 chloropicrin-fumigated-pear sous as compared to the nonfumigated check soils. Increase in seedling growth in the 14 soils varied from 50% to more than 400% with both apple and pear. The lack of response of pear and apple seedlings to soil fumigation in 5 soils may be due to low soil pH, high soil arsenic levels and high soil phosphorous fixing capacity. Counts of plant parasitic nematodes (primarily Pratylenchus spp.) were generally low in all but one soil.

Open Access

Abstract

Apple trees (Malus domestica Borkh.) grown in soil fumigated with methyl bromide showed a significant increase in growth as measured by trunk circumference. The increase in trunk circumference from fumigation varied from 33 to 49% after 6 to 8 years. Fruit production increased from 2- to 4-fold during the same period. Soil pH, soil arsenic and nematode counts were not considered to be major factors in the lack of growth and fruit production for trees grown in unfumigated soil.

Open Access

Abstract

The growth of apple seedlings (Malus domestica Brokh.) is negatively correlated with soil arsenic and zero growth occurs at about 450 ppm total arsenic. Soil arsenic concentrations less than 150 ppm, which are frequently found in orchard soils, contribute less to the replant problem than biological factors. Growth of apple trees was increased 50% or more by preplant soil fumigation with methyl bromide or trichloronitromethane (chloropicrin) in 87.5% of the trials in 17 apple orchard soils tested. Non-specific plant pathogens in orchard soils attack cereals as well as apple seedlings, but apple orchard soils also contain an entity that specifically affects apples. This is probably the same unknown entity that is responsible for specific apple replant disease in Europe, Australia, and elsewhere.

Open Access

Abstract

Individual plants of 3 cultivars of peas (Pisum sativum L.)—‘Early Frosty’, ‘Darkskin Perfection 70A’, and ‘Puget 715’—were harvested to derive the plant yield components: numbers of filled pods, seeds/pod, seeds/plant, and fresh mean seed weight at processing maturity. These cultivars differed for number of filled pods, seeds/pods, and seeds/plant, but not for mean fresh seed weight. Following the conversion of yield component data to the log scale, a sequential yield component analysis was conducted via serial inclusion in a multiple regression equation. Both forward and backward sequential yield component analyses were computed. Across the 3 cultivars, the yield component contributing most to plant variation was pod number in both the forward and backward analysis. Contributions of the yield components to the total yield variation, ranked in declining order of importance for the forward analysis, were number of pods (73.6%), seeds/pod (13.6%), and weight/seed (12.9%). Backward analysis did not change the ranking, and the respective percentages were 47.9%, 40.6%, and 11.5%. Yields estimated through yield components were 7% to 14% higher than those measured from harvested plots.

Open Access