Veerendra Kumar Verma

Combining Ability Analysis and Its Relationship with Gene Action and Heterosis in Early Maturity Cauliflower

Eighty crosses derived from line (10)xa0×xa0tester (8) mating design along with their parents were evaluated to study the combing ability and its relationship to gene action and heterosis for eight yield and related traits in early maturity cauliflower. Analysis of genetic component of variance and variance due to specific combining ability (σ2sca) revealed preponderance of dominant variance and non-additive gene action for all of the traits except for days to 50xa0% curd maturity. In hybrids, contribution of lines was higher over the testers for all the traits. Among the lines cc-32E, 395aa and 14-4-17 and testers Sl-71, 23000 and Pusa Deepali were identified as promising general combiner for gross plant weight and marketable and net curd weight. However, hybrid cc-32Exa0×xa0Pusa Meghna was earliest (52xa0days) for curd maturity. For leaf area, plant height, curd compactness and gross plant weight the best combination was cc-32Exa0×xa023000. Among the hybrids, identified superior crosses with significantly highest level of heterosis over better parents were 395aaxa0×xa0Sel-7 (68.0xa0%), cc-32Exa0×xa023000 (48.19xa0%) and 395aaxa0×xa0Pusa Deepali (34.76xa0%) for economic trait marketable curd weight. Hence these hybrids can be further tested under different agro-climate for commercial production.

Effect of Mulching Materials on Soil Health, Yield and Quality Attributes of Broccoli Grown Under the Mid-Hill Conditions

Broccoli is an important cole crop, grown widely in the North Eastern states of India. The deficiency of soil moisture in mid-hills is one of the most limiting factors affecting the production and productivity of the crops. To evaluate the effect of different mulching materials on soil environment, productivity and quality aspect of broccoli (Hybrid Puspa), the experiment was conducted for three years during 2013–2016. Among the treatments, highest photosynthetic rate (34.81xa0mmolxa0m−2xa0s−1), transpiration rate (7.86xa0mmolxa0m−2xa0s−1), stomatal conductance (180.08xa0mmolxa0m−2s−1), low intercellular CO2 concentration (50.06xa0ppm), highest chlorophyll a (0.25xa0gxa0kg−1), b (0.06xa0gxa0kg−1) and a/b ratio (4.31) as well as anthocyanin content (0.62xa0mgxa0g−1) was recorded from the treatment T3 (Dry weed biomass mulch of Eupatorium and Ambrosia spp. @1xa0kgxa0m−2 area). Similarly, treatment T3 was also found to be superior for the number of leaves, leaf length, leaf weight, stalk length and weight, head length and diameter. The highest marketable head yield (22.75xa0txa0ha−1) was in T3 mulch and it was 57% higher over the control. Poly mulch has shown the higher soil moisture and temperature throughout growing period. The highest available nutrients such as soil organic carbon and NPK content were observed in poly mulch. For quality traits such as dry matter, total sugar, β-carotene and vitamin-C content, the control was superior. It was observed that, mulching has positive effect on the yield as well as quality and available biomass in this region can be a better alternative for the resource poor farmers of this region.

Genetic characterization of chayote [ Sechium edule (Jacq.) Swartz.] landraces of North Eastern Hills of India and conservation measure

Chayote or chow–chow is an underutilized cucurbit vegetable crop, widely cultivated by farmers in the backyards and Jhum lands for its tender leaves, fruits and tuberous root. In order to initiate crop improvement program in this crop, the present study was undertaken to assess the genetic variations in the 74 chow–chow landraces collected from the North Eastern Hill region of India. Wide variations for fruit colors, fruit length (6.5–21.5xa0cm), fruit width (4.2–10.7xa0cm), fruit weight (60–560xa0g), vitamin-C (2.6–13.8xa0mg/100xa0g), reducing sugar (0.18–2.77%), total sugar (1.09–2.94%) and phenol content (0.17–3.85xa0mg/100xa0g FW) were recorded among the landraces. All the landraces were also characterized using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers. In RAPD analyses, out of 28 primers a total of 198 reproducible amplicons were formed at an average of 7.01 per primer and an overall polymorphism of 88.38%. Eight fragments were specific to landraces with light green fruits. Four fragments were observed to be specific to RCSC-22 (dark green fruits) and another four specific to a RCSC-30 (pale yellow fruits). Out of 30 ISSR, only 5 primers generated a total of 32 reproducible amplicons with an average of 6.4 per primer and overall polymorphism of 62.5%. The pair wise similarity coefficient values ranged from 0.55 to 0.96. The grouping of landraces in cluster analysis was found to be independent of their respective geographic locations. The cuttings of suckers and shoot top (2xa0months old) treated with indole-3-butyric acid (200xa0mgxa0l−1) provide an alternative for the conservation of the diverse genetic materials to the researchers.

Impact of Abiotic Stresses on Horticulture and Strategies for Mitigation in Northeastern India

The northeastern region is considered to be the richest reservoir of genetic variability of large number of horticultural crops. Changes in weather parameters have profound impacts on the livelihood of people and their ecosystem as whole. These problems can be mitigated by the selection of suitable cultivars of fruits, vegetables and spices crops which have the potential to grow under diverse weather conditions. Protected cultivation of high-value vegetable crops like tomato, capsicum and cucumber provides means for round-the-year production with protection against low temperature and heavy rains. Drip irrigation is the most suitable system for efficient utilization of water especially for the horticultural crops. The appropriate techniques to overcome the impact of climate change are necessary to protect our biodiversity and for feeding the fast-growing population. Awareness and educational programmes for the growers, modification of present horticultural practices and greater use of greenhouse technology are some of the solutions to minimize the effect of climate change.