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The present study entitled “Genotypic evaluation and in vitro multiplication of anthurium (Anthurium andreanum Linden) hybrids” was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, during 2017-19. The study was undertaken to evaluate anthurium hybrids for commercial qualities and their mass multiplication through in vitro techniques.
For variability analysis, 20 Anthurium andreanum Linden hybrid genotypes maintained at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani were utilized. When the selected hybrids were evaluated in completely randomized design with five replications, wide range of variations were observed among the qualitative as well as quantitative traits. The mean number of inflorescence year-1 ranged between 6.4 (HR x MR) and 2.2 (CR x KR). Spathe size was maximum for HoR x KR (112.30 cm2) and the minimum for HR x MR (27.60 cm2). The longest post-harvest vase life was observed for HoR x KR (24.4 days) which was on par with LJ x OG (23.4 days).
The components of variation namely genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were analysed. High PCV and GCV were observed for the characters number of suckers plant-1, number of leaves spadices-1 plant-1 year-1, spathe size, leaf area, number of flowers spadix-1, spadix length, duration of interphase, inclination of candle with spathe, anthocyanin content, vase life and number of inflorescence year-1. Thus, selection for these characters would result in improvement of the genotype.
High heritability coupled with high genetic advance were observed for plant height, leaf area, number of leaves spadices-1 plant-1 year-1, spathe size, spadix length, number of flowers spadix-1, days to initiation of female phase, duration of female phase, inclination of candle with spathe, anthocyanin content, vase life and number of inflorescence year-1. This indicated that expression of these traits were controlled by additive gene action and improvement could be achieved for these traits by direct phenotypic selection.
Correlation analysis with genotypic correlation coefficients revealed significant positive correlation of number of inflorescence year-1 with characters such as number of leaves spadices-1 plant-1 year-1, number of suckers plant-1 and vase life. An improvement in positively correlated characters would enhance the number of inflorescence year-1. Path coefficients were worked out with number of inflorescence year-1 as the dependent variable and other correlated characters as component variables revealed that all the three positively significant, correlated characters had positive direct effect with the dependent variable. Path analysis further proved direct association of traits such as number of leaves spadices-1 plant-1 year-1, number of suckers plant-1 and vase life with flower yield of anthurium hybrids accounting for more than 70 per cent of variation in flower yield.
From experiment I, six hybrid genotypes namely HR x MR, LJ x OG, OG x NO, HoR x KR, PR x HR and HR x LR with superior flower yield attributing traits and qualitative characters were selected for in vitro mass multiplication study. For in vitro culture, pale greenish brown young leaf lamina, 5 to 10 days after unfolding of leaf, collected from healthy and mature plants were used as explant. Proper control measures were taken for control of bacterial blight and anthracnose diseases so as to obtain disease free explants. Surface sterilization of leaf explants with 5.0 per cent sodium hypochlorite for 10 minutes followed by 0.1 per cent mercuric chloride for 5 minutes was found to be the best and resulted in 87.5 per cent explant survival. For all the hybrids the highest callus induction percentage was recorded by modified half strength MS medium supplemented with 200 mg L-1 NH4NO3 + 1.0 mg L-1 BA + 0.5 mg L-1 2,4 D + 30 g L-1 sucrose + 6.0 g L-1 agar. The explants were cultured in darkness for callus induction and later the callus was subcultured in the same culture medium for two months for multiplication.
For shoot regeneration, the multiplied callus was subcultured to regeneration medium and a photoperiod of 16 hours light and eight hours dark was provided. Of the various regeneration treatments, half strength MS medium supplemented with 0.5 mg L-1 BA showed shoot initiation response ranging from 50.0 (LJ x OG and HR x LR) to 87.5 (OG x NO and HoR x KR) per cent among the hybrids. The fastest shoot regeneration was observed for the hybrid HR x MR (62.20 days) and slowest for LJ x OG (77.25 days). Rooting response preceded shooting response in all the hybrids in the same regeneration medium.
To summarize the research results revealed the presence of wide range of variability among the 20 anthurium hybrid genotypes for the 29 characters studied. Most of the quantitative traits were controlled by additive gene action permitting direct selection for improvement. Traits such as number of leaves spadices -1 plant-1 year-1, number of suckers plant-1 and vase life had positive significant correlation and direct association with flower yield in anthurium hybrids. Genotypic differences were evident from in vitro mass multiplication studies on the six superior hybrids. Modified half strength MS medium supplemented with 200 mg L-1 NH4NO3 + 1.0 mg L-1 BA + 0.5 mg L-1 2,4 D + 30 g L-1 sucrose + 6.0 g L-1 agar was the most suitable for callus induction and callus multiplication while shoot initiation, proliferation of shoot and root were the highest and faster in the same basal medium supplemented with 0.5 mg L-1 BA. Large scale multiplication of the superior hybrids and profit generation can be achieved through the tissue culture protocol that was standardized in the present study. The promising commercially superior anthurium hybrids identified in the study can be used in further crop improvement programmes.