Studies on influence of modified atmospheric storage conditions on biochemical parameters in pigeonpea seeds

An experiment was conducted to study the influence of modified atmospheric storage conditions on biochemical parameters of pigeonpea seeds. The experiment was conducted at the Department of Seed Science and Technology, College of Agriculture, Raichur, Karnataka. The seeds are exposed to various gaseous combinationsand stored in 700 gauge polyethylene bag for ten months during July-2012 to April- 2013. The results revealed that, the seeds exposed to gaseous combination of 40% N2+00% O2+ 60% CO2 showed less reduction in dehydrogenase enzyme activity and protein content (0.276 OD (optical density) value, 19.33 % respectively) as compared to the control (0.211 OD value and 18.13 % respectively) after ten months of storage. In addition less seed leachate (2.029 dSm-1) was recorded in gaseous combination of 40% N2+00% O2+ 60% CO2 as compared to control (2.207dSm-1). It indicates the potential use of modified atmospheric storage technology for maintenance of seed viability and vigour during storage in pulses.

Assessment of soybean (Glycine max) vigour by the seed leachate conductivity assay

Conductivity of seed leachates is inversely correlated with germination and growth of soybean, <i>Glycine max</i> (L.) Merr., at low temperatures. It is concluded that the seed leachate conductivity assay can be employed to assess soybean seed vigour. Cold tolerance of soybean can markedly be enhanced by increasing the hydration level of the seeds to at least 20% by means of exposure of the seeds to HRH (water saturated atmosphere) for 4 days. It is suggested that increased vigour following HRH exposure is due to re-establishment of the cell membrane integrity in the course of exposure.

Dependence of the legume seeds vigour on their maturity and method of harvest

Several methods were used to study 'the vigour and viability of legume seeds <em>(Pisum sativum </em>L. cv. Hamil, <em>Piston arvense </em>L. cv. Mazurska and <em>Lupinus luteus </em>L. cv. Tomik) harvested at three main stages of seed repening (green, wax and full). The seeds were tested immediately after harvest (series A) and after two weeks of storage in pods (series B). It was found that: 1) the vigour of ripening legume seeds increases with maturation; 2) post-harvest storage in pods increases the degree of ripeness and. consequently. vigour; 3) seeds attain full vigour later than full viability; 4) seed leachate conductivity method gives erroneous results in assessing the vigour of immature seeds: 5) full vigour of maturing seeds of various degrees of ripeness can be determined by simultaneous application of both biological (eg. seedling growth analysis, VI) and biochemical (e.g. total dehydrogenase activity) methods.

Effects of genotype and environment on seed yield and quality of rice

Seed yield and seed quality determine much of the value of rice (Oryza sativa L.) crops to the producers. The effects of genotype and environment on seed yield and quality were investigated using 12 rice genotypes grown during 3 years (2000–2003) at four different sowing dates in India, where detailed environmental data were collected. Yield, seed weight, proportion of seed setting and quality in terms of potential seed longevity, proportion of discoloured seeds, seed leachate conductivity and percentage germination were evaluated. The results were subjected to analysis of variance and the influence of environmental factors was evaluated by correlation analysis. Analysis of variance suggested that proportion of seed setting, seed leachate conductivity, potential seed longevity, percentage seed germination and proportion of seed discoloration were influenced more by environmental effects than by genotypic effects. In contrast, yield, panicle number, seed weight, and proportion of high-density grains were influenced more by genotypic than by environmental effects. The significant interaction effects of genotype and environment for all characteristics were attributed to differential resistance of genotypes to lodging (caused by increased plant height, low radiation and excessive rain at the time of grain filling) and were associated with fewer panicles harvested, lower seed setting and lower seed weight. Correlation analysis suggested that warm weather conditions with high solar radiation and without excessive rains during grain filling stage gave the best rice seed yield with high quality.

Seed Maturity and Desiccation Affect Carbohydrate Composition and Leachate Conductivity in shrunken-2 Sweet Corn

This study was conducted to determine if changes in the raffinose: sucrose ratio in embryos of shrunken-2 sweet corn (Zea mays L.) hybrids were related to differences in seed leachate conductivity between two hybrids harvested at four maturities and artificially dried to 0.10 g H2O/g fresh weight. The ratio of raffinose: sucrose differed for `Crisp N' Sweet 710' (CNS) and `How Sweet It Is' (HSII). The mass ratio of raffinose: sucrose in CNS was >0.3 in seed harvested between 0.44 to 0.64 g H2O/g fresh weight and increased as seed dried from the initial harvest moisture to 0.10 g H2O/g fresh weight. Raffinose: sucrose ratios of HSII were <0.3 at all harvests between 0.55 to 0.72 g H2O/g fresh weight, but changes during desiccation were not as pronounced. Leachate conductivity of whole seeds of CNS and HSII decreased as seeds were harvested at progressively lower moisture contents. We suggest that a higher raffinose: sucrose ratio may be indicative of increased seed vigor in shrunken-2 hybrids.

Studies on water damage in mungbean. II. Electrical conductivity of seed leachate as an assay of level of damage

Weather-damaged seeds of mungbean are unsuitable for the production of bean sprouts and some other food uses. The breeding of resistant cultivars requires an understanding of the weathering process and the use of suitable criteria for measuring the degree of weather damage. The aim of this research was to describe the effect of weathering on the electrical conductivity of leachate from exposed seeds and to evaluate this technique as a means of discriminating among levels of weather damage. Seeds were weathered in the field or immersed in water in the laboratory for varying durations during one or more cycles of wetting and drying. Leachate conductivities generally increased with increasing visual damage and decreasing viability of seeds. When measurements of conductivity were delayed, the results appeared to be confounded by the extent to which solutes were lost during previous exposure/s to weathering. Measurements soon after immersion tended to reduce this effect and to better reflect the level of weather damage in seeds of mungbean. It was concluded that leachate conductivity technique can provide a reliable assay of weather damage in mungbean. When seeds have been exposed to severe weathering, however, the relationship breaks down, and the technique can give misleading results.