Effect of some physical and chemical factors on germination of conidia of Alternaria alternata (Fries) Keissler causing fruit rot of apple was investigated. The germination was maximum at 30 deg C, 100 % RH and at 5.5 pH Syllit, amongst the 11 fungicides and Planofix, amongst the 5 growth regulators caused maximum inhibition of conidial germination

Seed lot samples were brought from local seed dealers Maeklong Basin of Thailand e.g. Karnchana-Buri, Supun-Buri, Raj-Buri, Nakorn-Pathom, Samusakorn, Samusongkram and Petch-Buri, during November 1983 to November 1984. The observations were made on the types of containers, packaging materials and storage condition. Then, each samples were taken for seed moisture content determination, physical purity test and germination test. Seed quality was found that the physical purity percentage was suitable. Meanwhile seed germinations of sweet corn, yard long bean and soybean had enough high quality, but the other vegetable seed lots were lower than the minimum standard of germination percentage given in ministry notice which enforced by Seed Act B.E. 2518, and could not use them. The unsuitable storage condition and management of the seed dealers may be not effective for seed quality control.

Lowland soil differed in pore size distribution and moisture status from upland soils of similar texture. Pore size and moisture status strongly influenced other physical properties of the soil that affect plant growth. A predominance of small pores increased moisture retention, decreases aeration, altered heat relations and caused a rigid soil structure. Favorable temperature and good seed-soil contact to ensure adequate water supply were necessary for germination. Proper aeration and low soil strength were necessary for seedling emergence. Root growth and function also required suitable regimes of air, water and temperature. If root growth was efficacious, so also may be above ground plant growth and yield. In rice-based cropping systems, the successive crops may require differing soil physical environments, and soils must be managed accordingly

Abstract: This manual covers four areas basic to agronomy: soils and fertilizers, seeds, weeds, and crop production. The section on soils and fertilizers covers the physical make up of soil. Activities include having soil tests run on top soil, sub soil, and sand to compare their mineral content and testing these soils' water capacity. The last section on soil covers soil conservation concerns and activities. The section on seeds covers seed parts and the germination principle, keeping a list of everything you eat and determining whether it is indirectly or directly from a seed, and germinating seeds under varying conditions and stresses. The section on weeds addresses classification of plants as weeds, and information on herbicide use and safety. On the subject of crop production much emphasis is given to why certain crops fare well in Georgia and others do not. Also included is an exercise comparing different varieties of corn and their performance.

Quackgrass (Agropyron repens L. Beauv.) has been previously reported to possess allelopathic potential. Both the shoots and rhizomes of quackgrass have been shown to contain inhibitors of seed germination and crop growth. We recently observed chlorosis and decreases in nodulation in snapbeans that were planted into quackgrass infested sites. The objective of this study was to determine if nodulation, N,₂ fixation and legume growth were inhibited in the presence of living or herbicidally treated quackgrass. Soybeans (Glycine max L. Merr.) and navybeans and snapbeans (Phaseolus vulgarls L.) were grown both in greenhouse and field experiments in living or killed quackgrass. Inoculated legumes were seeded in the following regimes: 1) living quackgrass sod which was regularly mowed; 2) glyphosate [N-(phosphonomethyl) glycine] -treated quackgrass sod 3) soil from quackgrass sod from which plant material was removed by sieving or raking; 4) a control soil of similar type and physical structure free from quackgrass infestation. Nodulation and plant growth were measured by recording nodule number and fresh weight and root and shoot weights before flowering. Nitrogen fixation was estimated by the acetylene reduction assay. Legumes grown in mowed quackgrass sod in the greenhouse and in the field exhibited decreased nodule number, nodule fresh weight and N, fixation when compared to legumes grown under similar conditions in screened quackgrass soil or the control soil. Shoot and root weights were also significantly decreased in field and greenhouse experiments when legumes were grown in living quackgrassod. In many cases, legume nodulation and growth were decreased in glyphosate-treated quackgrassod as compared to screened quackgrass soil or the control soil. Decreases in legume growth and nodulation in the presence of quackgrass may be attributed to allelochemical effects.