Journal of Horticultural Sciences

Gayatri Khangjarakpam ¹, Rajiv Kumar ², G. K. Seetharamu ¹, T. Manjunatha Rao ², M. V. Dhananjaya ², R. Venugopalan ³, K. Padmini ⁴

Affiliations
1 Department of Floriculture, Medicinal and Aromatic Plants, Uttar Banga Krishi Viswavidyalaya, Koch Vihar, West Bengal, IN
2 Division of Ornamental Crops, ICAR-Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bengaluru - 560 089, IN
3 Section of Economics and Statistics, IIHR, Bengaluru, IN
4 Section of Seed Science and Technology, IIHR, Bengaluru, IN

Abstract

A field study was conducted to estimate genetic variability, heritability and genetic advance in 20 genotypes of China aster for 15 traits during the year 2012-13 in Randomized Complete Block Design, with three replications. Results revealed that the magnitude of phenotypic co-efficient of variation (PCV) was higher than genotypic co-efficient of variation (GCV) for all the traits studied. Narrow differences between GCV and PCV were recorded in all the characters except flowering duration, vase-life and shelf-life, indicating little environmental influence on expression of these characters. High (>20%) GCV and PCV were recorded for plant height, number of branches and leaves per plant, flower diameter, number of ray and disc florets/flower head, stalk length, and, number and weight of flowers/plant. Heritability estimates ranged from 28.30% (flowering duration) to 99.54% (flower diameter). High heritability (<60%) was observed for all the traits except flowering duration. High heritability, coupled with high genetic advance as per cent mean, was recorded for flower diameter, stalk-length, number of branches/plant, weight of flowers/plant, days to first flower opening, days to 50 per cent flowering, plant height, number of leaves/plant, number of ray and disc florets/flower head, number of flowers/plant, indicating a possible role of additive gene action. Thus, these traits can be improved through selection and breeding.

Keywords

China Aster, Genetic Variability, Heritability, Genetic Advance.

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K. Padmini ¹, R. Veere Gowda ¹, L. B. Naik ¹

Affiliations
1 Section of Seed Science and Technology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore-560 089, IN

Abstract

An experiment was conducted at the Indian Institute of Horticultural Research, Bangalore, in Rabi season during 2001-2002 and 2002-2003 to study the flowering of Cytoplasmic Male Sterile Lines CMS (A) and pollinator lines (C) of onion cv. Arka Lalima for working out effective synchrony in hybrid seed production. Results indicated that days to 100% flowering and days to complete flowering in a plant varied significantly in the parental lines and C line was found to be earlier than A line by 12 days and 25 days, respectively. The duration of flowering in a plant was also less in C line (23 days) than in A line (29 days). Due to lack of floral synchrony between parental lines, pollen availability becomes a limiting factor in hybrid seed production in cv. Arka Lalima. Delay in planting of C lines by a week after planting A lines resulted in synchronised flowering of parental lines at peak flowering stage. This also resulted in higher fruit set (80%) and hybrid seed yield (15g/plant) as against planting of A and C lines simultaneously (29.54% and 0.38g, respectively).

Keywords

Cytoplasmic Male Sterility, Flowering, Hybrid Seed Production, Onion, Synchronization.

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K. Padmini ¹, L. B. Naik ¹

Affiliations
1 Section of Seed Science and Technology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore-560 089, IN

Abstract

Studies were conducted during 2002-2005 (Rabi season) to evaluate the extent of genetic contamination in round fruited ridge gourd (recessive) vehen grown for seed production under open field conditions. The round fruited ridge gourd was sown at 200 m, 400 m, 600 m and 800 m distance from Arlia Sumeet (long fruited) which acted as the local marker (dominant). The highest percentage of genetic contamination was recorded at a distance of 200 m from the contaminator (Arka Sumeet) (28.62% and 88.1%, respectively, in the years 2003 and 2005). It was also observed that there was a gradual reduction in contamination level with increasing distance from 28.62 to 17.44% at 600 m distance in 2003 and 88.11% at 800 m to 74.23% in 2005. The lowest percentage of contamination was recorded at the highest isolation distance (at 600 m, 17.44% in 2003 and at 800 m, 74.24% in 2005), although it is not within the prescribed maximum permissible limit of genetic contamination (1 and 2% for foundation and certified seed respectively). In the present study, in all the isolation distances studied, the level of contamination is well above the permissible minimum seed certification standards (99 and 98 % genetic purity for Foundation and Certified seed respectively). Hence, any reduction in the isolation distance from the prescribed (800 m) isolation would drastically affect the genetic purity of ridge gourd for seed production under open field conditions.

Keywords

Cucurbits, Genetic Purity, Isolation, Ridge Gourd, Seed Production.

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