Standardization of propagation techniques in avacado (Persea americana Mill.)

Abstract

Avocado (Persea americana Mill.) is one of the choicest salad fruit in the world. It is also known as butter fruit and belongs to the family Lauracaeae. The fruit is rich in Mono Unsaturated Fatty Acids (MUFA), vitamins, minerals and hence considered as an ideal fruit crop for nutritional security. Avocado fetches very high price in the market and so it is highly remunerative for the farmers if grown on a commercial basis. Being a region of humid tropics, Kerala is ideal for the cultivation of avocado. Though there is enough potential to commercialize this crop the lack of awareness about the benefits of this fruit and the low availability of quality planting material limits its commercial cultivation in our state. So the present study entitled “Standardization of propagation techniques in avocado (Persea americana Mill.)” was carried out in the Department of Fruit Science, College of Horticulture, Vellanikkara during the year 2019-2020 with the objective of standardizing an effective method of propagation in this crop. The research programme was conducted as two experiments. In the first experiment, trials were conducted to standardize the media for seed propagation. The experiment was laid out in CRD with four treatments replicated four times with six plants in each replication. Treatments included four different media like T1 (Rock sand), T2 (Rock sand+Soil+FYM, 1:1:1), T3 (Soil+Cocopeat+Goat manure, 1:1:1) and T4 (Soil+Cocopeat+Vermicompost, 1:1:1). The treatment T3 was found to be the best media as early seed germination and highest germination percentage was observed in this media. A trial was also conducted to know whether seed treatment if given to the seeds before sowing have any effect on improving seed germination and germination percentage of the seeds. The media used for sowing seeds was T3 (Soil+Cocopeat+Goat manure, 1:1:1). Seed treatments included S1 (seed sown without seed coat), S2 (seed sown after mechanical scarification), S3 (seed sown after giving a cut both at the top and bottom portion of the seed) and S4 (seed sown with seed coat) replicated four times with six plants in each replication. Observations on vegetative and root characters were noted at 15 days interval for three months after sowing. Second experiment was conducted to evaluate various vegetative propagation methods in avocado. Experiment was laid out in CRD with twelve treatments replicated four times with six plants in each replication. Treatments included T1 (Terminal leafy cutting), T2 (Softwood cutting), T3 (Semi hardwood cutting), T4 (Hardwood cutting), T5 (Air layering (coirpith compost as the media), T6 (Air layering (sphagnum as the media), T7 (Epicotyl grafting), T8 (Softwood grafting), T9 (Whip grafting), T10 (Whip and tongue grafting), T11 (T Budding) and T12 (Patch budding). Observations on vegetative characters were noted at 15 days interval for three months. From the results of the first experiment it was found that both media and seed treatments were having significant influence on time taken for initial seed germination. Seeds grown in T3 media (Soil+Cocopeat+Goat manure, 1:1:1) germinated early (21.4 days after sowing) but when S3 (seed sown after giving a cut both at the top and bottom portion of the seed) treatment was given to seeds, germination was speeded up (18.9 days). Similarly, germination percentage was also seen enhanced by S3 treatment in T3 media from 87.75 % to 91.5%. Potting media was found to have no significant effect on plant height. The treatment S3 recorded highest plant height at 45, 75 and 90 days after sowing. Among media, T2 (Rock sand+Soil+FYM,1:1:1) was found to be superior with respect to number of leaves per plant at 30, 75 and 90 days after sowing . With regard to seed treatment, maximum number of leaves were noted in S1 after 30, 45, 60 and 75 days after sowing. No significant difference was observed among the treatments with regard to number of branches, number of seedlings arising from a seed and girth of seedlings. Longest roots were noted in T4 media (Soil+Cocopeat+Vermicompost, 1:1:1). In the second experiment propagation methods like terminal leafy cutting, softwood cutting, semi hardwood cutting, hardwood cutting and air layering were not found to be successful in multiplying avocado plants. Though the treatment T7 (Epicotyl grafting) took only minimum number of days for initial sprouting (25.37 days), survival percentage was found to be the highest (72.17%) in T8 (softwood grafting). With regard to maximum number of leaves (25.62) and branches (4.19), T10 (Whip and tongue grafting) was found to be superior over all the other methods but with very low survival percentage (20.77 %) when compared to softwood grafting. Again T8 (Softwood grafting) recorded maximum shoot length (36.38 cm) among all the other treatments during the period of observation. In the present study, the best media was found to be T3 (Soil+Cocopeat+Goat Manure (1:1:1)) and and the best seed treatment was S3 (seed sown after cutting the top and bottom of the seed) with early seed germination, highest germination percentage, seedling height. Root length was found to be the highest in T4 (Soil+Cocopeat+Vermicompost, 1:1:1). In the second experiment, softwood grafting (T8) was found to be the best among the vegetative propagation methods with highest survival percentage (72.17 %) and shoot length (46.64 cm).