. Germination and seedling growth using vermiculite and cork granulates as top coats. Tomato seeds germinated after 8.1 d when top coated with vermiculite, which was not different from the 8.3 d required for tomato seedscoated with cork granulates to germinate
The Agricultural Research Service of the United States Department of Agriculture announced the release of `Bettergreen' southernpea on 30 April 1991. `Bettergreen' is a cream-type cultivar that is homozygous for a newly discovered gene(s) conditioning a unique green cotyledon trait. `Bettergreen' can be harvested at the near-dry seed stage of maturity without loss of the seed's fresh green color. The color of the peas harvested upon reaching “dry-stage” maturity is light olive, and the color is present in both the seed coat and the cotyledons. The fresh peas are small (22 g per 100 peas), ovate to reniform in shape, and have excellent culinary quality. The dried peas have a smooth seed coat. `Bettergreen' is recommended for use as a home garden and fresh market cultivar for spring, mid-season, and fall plantings throughout the southeastern United States. It is particularly recommended for trial as a commercial processing cultivar for the frozen food industry.
Production of watermelons for seed consumption is popular in many regions of the world. In the Mediterranean area, large white seeds are preferred. Six breeding lines were selected for investigating the nature of black spot, an undesirable feature reducing the commercial value of the seeds. Black spot is expressed as blackened areas of the seed coat, mostly near the margin in mild cases, but extending over much of the seed coat in severe cases. Sowing date had a significant effect on expression of black spot. Seeds that developed in early summer (June) had low frequency and severity of black spot expression, whereas seeds that developed later in the summer (July–August) had markedly increased expression. Large differences were also observed among the breeding lines. There was a significant negative correlation between severity of black spot and seed weight, suggesting that black spot is a stress-related phenomenon.
Transverse cracking of cotyledons, (TVC), varied from 0 to 95% among bean cultivars and was enhanced by planting dry seed in wet soils. A more reliable indication of TVC potential was obtained if the seed was placed in small beakers and covered with water. Covering the hilum with grease slowed imbibition and reduced TVC in tolerant lines. Soaking for 45 minutes in ethanol prior to imbibition in water accelerated imbibition and increased TVC. Seed coat removal prior to imbibition further enhanced imbibition and increased TVC. None of these 3 treatments changed the relative amount of TVC, but seed coat nicking or removal prior to imbibition gave the most reliable test.
Potassium and Mg in cotyledons were negatively correlated with cultivar susceptibility. Calcium was sometimes significantly correlated with TVC in seed grown in a given location, but the correlations could be lacking or of opposite sign in seed grown elsewhere.
Seeds of Zamia furfuracea Ait. (cardboard plant) were treated following removal of the sarcotesta (fleshy seed coat) with concentrated H2SO4 and 1000 ppm GA3 in a 4 × 4 factorial combination. The highest total germination of 82.2% in an average time of 74.5 days (germination value = 0.070) was achieved when seeds were exposed to H2SO4 for 15 minutes. Average number of days to germination was reduced to 37.7 when 30 minutes of H2SO4 treatment was followed by 24-hour GA3 soak without significantly affecting percent germination (germination value = 0.103). Interactions of H2SO4 and GA3 are explained by the effect of H2SO4 on sclerotesta (stony seed coat) thickness and the effect of GA3 on the accelerated development of an immature embryo.
Pseudoembryos, produced from endothelial proliferation, were found in parthenocarpic fruits of ‘Severianin’ tomato (Lycopersicon esculentum Mill.)· The pseudoembryos did not increase in size after 12 days after anthesis and no endosperm or embryo occurred. At maturity, pseudoembryos became yellow-white in color and had developed a seed coat and thickened radial walls which appeared like hairs. Parthenocarpic fruits had complete locular development, similar to seeded fruits.
Seeds of hairy indigo, a tropical legume cover crop, are dormant due to hard seed coats. Immersion of the seed in concentrated H2SO4 for 20 or 30 minutes or hot water at 70° to 80°C for 2 minutes, significantly increased the germination percentage and rate. H2SO4 was more effective than hot water. Redrying the seed after treatment improved the effectiveness of the treatments slightly.
Rate and percent germination of Zamia integrifolia Ait. and Z. furfuracea L.f. can be significantly improved by seed scarification. Reported germination times of up to a year or more can be reduced to 1 to 3 months under greenhouse conditions if the outer fleshy seed coat is removed and the inner stony layer scarified. Rate and percent germination vary with placement of scarification cut and species. Germination of 80 to 100% in 1 week were obtained for Z. integrifolia under laboratory conditions.
Antioxidants are important to human health, as they are responsible for reduced risk of diseases such as cancer, hence motivating researchers to examine crop plants for available antioxidant compounds. There is also increasing interest in the use of antioxidants from plants instead of synthetic products. In order to evaluate variability of antioxidant activity (AOA) in cowpea, 697 cowpea accessions from the U.S. Cowpea Core Collection obtained from the Regional Plant Introduction Station, Griffin, Ga., were analyzed for AOA expressed as μg trolox equivalents/gdw. Two grams of dry seed from each accession were ground, extracted in methanol and analyzed for AOA using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), method. A large variation in AOA within the core collection, ranging from 1859 μg·g–1 dw (PI 180355, pigmented seed coat) to 42.6 μg·g–1 dw (PI 583100, cream seed coat), was observed. A least significant difference of 131.5 (p =0.05) was obtained. Higher AOA was manifested by accessions with pigmented seed coats. Accessions that were speckled, striped or had a pigmented eye were moderate in AOA, while the cream types were generally low. Variability in AOA observed among cowpea accessions suggests that breeding for high AOA can be successfully conducted. Accessions with high AOA could also be used to extract antioxidants for industrial purposes. Some accessions were a mixture of various colors and patterns, making it difficult to classify them into a particular category. Therefore, there is need to ensure purity of these accessions by ascertaining whether the mixtures are physical, i.e., combination of different varieties, or are composed of segregating material.
Redbud (Cercis canadensis) is a small woody ornamental legume that has a hard seed coat, which imposes physical dormancy, typical of many legumes. Redbud also possesses an internal embryo dormancy that must be overcome by stratification. In order to observe the relationship between anatomy and germination, seeds were embedded in JB-4 resin during various developmental and germination stages. The seeds were cut longitudinally with a glass bladed microtome, to observe the radicle, vascular traces and testa. It appears that the vascular traces left from the funiculus serve as a weak point in non-dormant seeds that allows the radicle to rupture the testa during germination.