In present investigation, the seeds of Helianthus annuus L. variety Modern were treated with nine different concentrations (0.05%, 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.50%, 1.75% and 2.00%) of caffeine to raise the M1 generation and the effect of caffeine on seedling height on 30 th day of sowing, mature plant height, days to maturity and yield parameters was observed. Generally, the lower doses of caffeine were found stimulatory for the seedling height on 30 th day of sowing, mature plant height, days to maturity and 100-seeds weight. While, the number of seeds in treated plants showed a dose dependent increase with the increasing doses of mutagen. It shows that caffeine in its lower doses has stimulatory effect on growth and yield in Helianthus annuus L. while the higher doses have inhibitory effect and reduce the growth and yield upto some extent except number of seeds.

Armillarioids, including the genera Armillaria, Desarmillaria and Guyanagaster, represent white-rot specific fungal saprotrophs with soilborne pathogenic potentials on woody hosts. They propagate in the soil by root-like rhizomorphs, connecting between susceptible root sections of their hosts, and often forming extended colonies in native forests. Pathogenic abilities of Armillaria and Desarmillaria genets can readily manifest in compromised hosts, or hosts with full vigour can be invaded by virulent mycelia when exposed to a larger number of newly formed genets. Armillaria root rot-related symptoms are indicators of ecological imbalances in native forests and plantations at the rhizosphere levels, often related to abiotic environmental threats, and most likely unfavourable changes in the microbiome compositions in the interactive zone of the roots. The less-studied biotic impacts that contribute to armillarioid host infection include fungi and insects, as well as forest conditions. On the other hand, negative biotic impactors, like bacterial communities, antagonistic fungi, nematodes and plant-derived substances may find applications in the environment-friendly, biological control of armillarioid root diseases, which can be used instead of, or in combination with the classical, but frequently problematic silvicultural and chemical control measures.

The better understanding of selecting an effective and efficient mutagen may provide better chances to induce high frequency of desirable mutations in any crop breeding program. Present study was carried out with the eggplant (Solanum melongena) variety Pusa Uttam to test the mutagenic effectiveness and efficiency of gamma ray, methyl methane sulphonate (MMS), dimethylsulphate (DMS) and diethyl sulphate (DES) to induce maximum macro-mutations which could eventually be exploited in future as viable and economically important traits. Mutagenic effectiveness and efficiency were calculated as per the standard formulae. In general, the results indicated that mutagenic effectiveness and efficiency decreased with increase in mutagenic treatments. Moreover, the lower or intermediate treatments of gamma rays as well as the alkylating agents were found more effective and efficient in creating maximum mutations with less biological damage. The order of mutagenic effectiveness was MMS>DMS>DES>gamma ray. The order of mutagenic efficiency with regard to inhibition in germination (Mp/I) was same as the effectiveness, while, the orders of efficiency with regard to pollen sterility (Mp/S) was DMS>DES>MMS>gamma ray. The alkylating agents were found to be more potent than gamma rays in effectively and efficiently widening the genetic base of variability in eggplant and provided greater chances for selecting different desirable characters in future breeding program.

Three mutants isolated according to differed morphological traits were isolated from the M 2 progeny of gamma ray-irradiated Solanum melongena L. var. PPL, viz. PPL-j 3 (5kR), PPL-k 3-1 (15 kR), and PPL-k 3-2 (15 kR). The seeds of selected mutants of M 2 generation were collected individually and grown in M 3 generation, separately and data on various quantitative traits, such as plant height (cm), number of branches per plant, number of fruits per plant, fruit weight (g), fruit size (cm), 1000-seed weight (g), and yield (kg) per plant, were recorded for all three mutants. The mutants were morphologically quite distinct, as compared to the control and to each other. The average performance of different quantitative traits was better in a high yielding mutant (PPL-j 3) as compared to the control, while in other two mutants (PPL-k 3-1 and PPL-k 3-2), poor yield was observed. Cytological analysis revealed almost normal chromosomal set in mutant screened from 5kR irradiated population, except for a few chromosomal aberrations. The higher frequency of meiotic aberrations was recorded in mutants isolated from 15 kR irradiated population. However, the frequency of these chromosomal irregularities decreased at anaphase, exhibiting recovery at later stages. A reduction in pollen fertility was also recorded in mutants isolated from 15 kR, indicating low fruit set.