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The cause for the differences in germination ability of large and small confection sunflower (Helianthus annuus L.) seeds was investigated over 3 years. The source-sink relationship was manipulated to better explore the differences between seeds of various sizes and to study the role of the embryo and the pericarp (hull) in controlling germination ability. Percent germination of large seeds was significantly lower than that of small seeds when tests were performed at 15 °C. Increasing the ratio of leaf area to number of developing seeds caused an increase in mean seed mass, but resulted in a lower percentage of germination. Seed vigor, as measured by mean time to germination or to emergence of hulled seeds or by rate of root elongation, was negatively correlated with embryo mass, indicating that the low vigor of large seeds is not due to the mechanical barrier imposed by the hull. Analysis of electrolyte leakage confirmed the hypothesis that the low quality of large seeds results from a disturbance during the process of seed development.

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The fruit of several Opuntia species (prickly pear) are a good source of calcium, potassium, and ascorbic acid and are consumed fresh or processed as juices or preserves. Plants of Opuntia may be grown in arid and semiarid environments on marginal soils. Various cultivars, particularly in the species Opuntiaficus-indica, are grown commercially in the United States, Israel, Italy, Mexico, and South Africa. There is a need for new sources of genetic diversity and subsequent germplasm evaluation, and until recently, no publicly maintained germplasm collection of Opuntia existed in the United States. The purpose of this study was to evaluate fruit quality of 25 Opuntia accessions, originating from six countries, and maintained at the USDA collection at the National Arid Land Plant Genetic Resource Unit, Parlier, Calif. The largest fruits were harvested from plants of accessions PARL 201, 202, and 228 (227.6, 247.3, and 231.3 g/fruit, respectively). The hardest peel was on fruits of PARL 225 and 234 (both 3.7 kg), and fruit pulp of the same two accessions had the highest firmness (2.3 and 2.4 kg, respectively). Soluble solids in mature fruit varied from 6.1% (PARL 231) to 15.0% (PARL 254). The fruit color ranged from light yellow through orange, pink to dark purple. These characteristics and other traits such as fruit acidity, presence of spines, and seed mass/fruit indicated that the material represents a diverse germplasm collection, usable for future cultivar development.

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The effects of six applied N treatments differing by rates and frequencies of application on the yield and quality of pepper (Capsicum annuum var. annuum L. `Anaheim Chili') grown for seed was studied. The timing of N applications was based on crop phenology, leaf petiole nitrate-nitrogen concentrations (NO3-N) minimum thresholds, and scheduled calendar applications of fixed amounts of N. Solubilized NH4NO3 was applied through a trickle-irrigation system to ensure uniform and timely applications of N. Rate of mature (green and red) fruit production was unaffected by any treatment except weekly applications of 28 kg·ha-1 of N, which stopped production of mature fruit before all other treatments. Early season floral bud and flower production increased with increasing amounts of N. The two highest total N treatments produced more floral buds and flowers late in the season than the other treatments. Total fruit production was maximized at 240 kg N/ha. Differences in total fruit production due to frequency of N application resulted at the highest total N level. Red fruit production tended to be maximized with total seasonal applied N levels of 240 kg·ha-1 and below, although weekly applications of N reduced production. Total seed yield was a function of red fruit production. Pure-1ive seed (PLS) production was a function of total seed production. Nitrogen use efficiency (NUE) for red fruit production also decreased with N rates >240 kg·ha-1, but PLS yield and NUE decreased in a near-linear fashion as the amount of total seasonal applied N increased, regardless of application frequency. Season average NO3-N (AVE NO3-N) values >4500 mg·kg-1 had total seed and PLS yields less than those treatments <4000 mg·kg-1. Six-day germination percentage was reduced with weekly N applications of 14 kg·ha-1. Seed mass was reduced with weekly N applications of 28 kg·ha-1. Final germination percent, seedling root length and weight, and field emergence were unaffected by any of the N treatments. These findings indicate that different N management strategies are needed to maximize seed yield compared to fruit yield and, therefore, there may be an advantage to growing `Anaheim Chili' pepper specifically for seed.

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/high). Data from the three trials were analyzed separately. Response variables recorded in Fall 2014 were pod number, seed number, seed mass, seeds per pod, and mean seed mass (grams per seed). Pod number, pod mass, and g sn were recorded for Spring and Fall

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, was placed in each replicate greenhouse. Seed mass. To determine the effect of selection on seed mass, 100-seed weight was measured for the C 0 and C 3 populations. Seed was produced independently in Jan. 2015 and 2016, and June 2016 for some or all

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that may affect crop emergence is seed size. Edamame seed mass is ≈30 g/100-seed compared with 15 to 20 g/100-seed for grain-type soybean ( Bernard, 2005 ; Dong et al., 2014 ; Williams, 2015 ). The literature is inconclusive on how seed size affects

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variance and comparison of means for seed mass (SM), first germination count at 25 °C (FC25), total germination at 25 °C (TG25), first germination count at 35 °C (FC35), total germination at 35 °C (TG35), and thermotolerance ratio ( T35/T25 ) from 34

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diameter of 116.21 mm ( Table 1 ). The peel is mamillated (pronounced protrusions). Mean fruit mass was 638.73 g, peel mass was 282.14 g, and seed mass was 39.30 g, with a mean of 90 seeds. Compared with other sugar apples, ‘LeahReese’ is generally larger

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described subsequently for seeds. Table 1. Spinacia oleracea accessions obtained from the U.S. Department of Agricultural Resource Service, Germplasm Resources Information Network and Mou (2008) . Table 2. Mean seed mass ± sem , days to harvest ± sem

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of variance and Tukey's honestly significant difference ( α = 0.05) (Version 9.2; SAS Institute Inc., Cary, NC). In Expt. 1, the dependent variable was seed mass increase (%) on a dry mass basis. Although germination capacity (i.e., cumulative

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