Search Results
Abstract
As the concentration of the exogenously applied gibberellin GA4+7 increased from 1 to 100 ppm, 3 significant correlations were observed: 1) the number of days to first flowering decreased; 2) the peduncle length of the first flower increased; and 3) the number of visible peduncles on the primary phyllomorph increased. A subsequent application of 10 ppm naphthaleneacetic acid (NAA) generally had no effect on these results.
Five rates of urea-N each at two water levels (0.6 & 1.0 ETc) were applied to three varieties (Butte, Carmel, and NonPareil) of almonds [Prunus dulcis (Mil) D. A. Webb] planted in 1981 on a 3.65 × 5.47-m spacing (550 trees/ha) on Arbuckle gravelly loam (Fine-loamy, mixed, thermic Typic Haploxeralf). Trees were drip-irrigated to basins (three per tree) ≈7 cm deep and 30 cm in diameter, located 76 and 183 cm on either side of the trees in the tree row. N rates ranged from 0–57, 0–198, 0–454, 113–907, 170–1361, 227–1814, 227–1814, 170–1361, 113–907, 113–907, 113–907, 0–907, 0–907 and 0–907 g per tree, respectively, during 1982–1995 and were applied on a monthly basis in four to six increments beginning in April. Almond meat yields were >1500 kg·ha–1 in 1984 and as high as 3800 kg·ha–1 during the 12-year period for the 1.0 ETc water treatment and optimum N rate. Nitrogen response was generally in the 600–1000 kg·ha–1 range, with water treatment response in the 200–500 kg·ha–1 range. The three varieties generally responded to higher N and water rates in the order Butte > Carmel > NonPareil. Leaf analyses (three to six each year) were used to monitor treatment effects and evaluate need for other nutrients.
The biosolid soil amendment N-Viro Soil (NVS) and a Streptomyces isolate (S 99-60) were tested for effects on root-knot nematode [RKN (Meloidogyne incognita)] egg populations on cantaloupe (Cucumis melo). Application of 3% NVS (dry weight amendment/dry weight soil) in the soil mixture resulted in significant (P ≤ 0.01) suppression of RKN egg numbers on cantaloupe roots compared to all other treatments, including 1% NVS and untreated controls. Ammonia accumulation was higher with the 3% NVS amendment than with any other treatment. Adjustment of soil pH with calcium hydroxide [Ca(OH)2] to the same levels that resulted from NVS amendment did not suppress nematode populations. When cultured in yeast-malt extract broth and particularly in nutrient broth, S 99-60 was capable of producing a compound(s) that reduced RKN egg hatch and activity of second-stage juveniles. However, when this isolate was applied to soil and to seedling roots, no suppression of RKN egg populations was observed on cantaloupe roots. Combining S 99-60 with NVS or Ca(OH)2 did not result in enhanced nematode suppression compared to treatments applied individually. The results indicated that NVS application was effective at suppressing RKN populations through the accumulation of ammonia to levels lethal to the nematode in soil.
Abstract
Equipment for measuring water use of a greenhouse crop of up to ± 1 kg h-1 over 30 m2 is described. It is based on growing a crop in nutrient film, with a nutrient tank replenished from a water tank, and controlled by accurate level sensors. The water tank is suspended from a load cell interrogated at frequent intervals by a data logging computer. Examples of data collected are given. Peak daytime transpiration rates varied from 50 mg s-1 m-2 to 150 mg m2 s-1 with a maximum error of 5%. With low transpiration rates, the errors were increased, but accuracy could be improved by calculating the rates over a prolonged time interval.
The development and evaluation of new turfgrass cultivars require considerable resources. A systematic understanding of the breeders’ and distributors’ trait selection behavior can provide a basis for making adjustments and improvements based on industry needs and thus accelerate the breeding process and make it more efficient. The objective of this study is to investigate the selection priorities for turfgrass traits and identify the most influential factors affecting turfgrass breeders’ and distributors’ likelihood of selecting turfgrass traits. Results show that the most important trait clusters for both breeders and distributors were abiotic stress resistance and growth characteristics. Breeders were more likely than distributors to select appearance traits when setting trait priorities. Program characteristics such as program size, education level, and being a male respondent had positive effects on the reported likelihood of selecting studied turfgrass traits, and these effects varied for different trait clusters.
An online survey was conducted to investigate the current practices of and challenges for turfgrass breeders and turfgrass seed distributors (or sales staff) in the United States. We found that turfgrass seed breeders rated producers/growers and consumers as more important parties compared with other interested parties. However, variations in ratings were found for breeders/distributors according to different program characteristics. The volume of seed sales of the species was the most highly rated technical consideration for both breeders and distributors. Compared with distributors, breeders considered the following technical factors more important than others: funding, labor, field trial performance, diversity in working priorities, availability of germplasms, scheduling, and staff training. Costs, followed by resource allocation and resource availability, were rated as the most challenging factors when breeders were implementing priorities. Our findings provide important insight regarding breeding and distribution practices and management in the turfgrass industry.