Mango seedling variability depending upon different potting mixtures and seed types - a case of evaluation of statistics analysis.
Rossetti A. G., Cavalcante Júnior A. T., Freire F. das C. O.
Author Affiliation: Embrapa-Centro Nacional de Agroindústria Tropical, Caixa Postal 3761, CEP 60511-110 Fortaleza, CE, Brazil.
: 685-690
Abstract : A study was carried out for the first 60 days in an unshaded nursery and after grafting in a 30% shaded greenhouse in 2000, in a completely randomized block design in a split-plot with 3 replications. Ten plants of mango per experimental unit and 2 factors: plot with 3 types of seeds/containers (seedlings from nucellar embryos in polyvinyl chloride (PVC) pots, seedlings from nucellar embryos in polyethylene bags, and seedlings from zygotic embryos in polyethylene bags) and split-plot with 4 potting mixtures: (a) 2 parts of burned rice husk+1 part of straw+1 part of clay; (a) 1 part of burned rice husk+1 part of straw+1 part of clay; (c) 1 part of clay+1 part of sand+1 part of manure; and (d) 1 part of burned rice husk+1 part of organic compound. The polyethylene bags were 15.00×28.00 cm and 0.15 mm in thickness, with 2.50 kg of potting mixture. The PVC pots had 19.00 cm height, 62.00 mm external diameter and 52.00 mm internal diameter, with 0.2 kg of potting mixture. Seedlings were grafted with scions of mango cv. Tommy Atkins 60 days after transplanting. Seedling from zygotic embryos in PVC pots showed the best development on potting mixtures a and d, while seedlings from zygotic embryos in polyethylene bags showed the best performance on the potting mixtures a and b. The worst development either for plant height or number of leaves was detected in seedlings from nucellar embryos in polyethylene bags. The means were the lowest and there was no significant difference in relation to the potting mixtures. Although the statistical design had been reasonable, the low levels of fitting (66.59 and 54.02% for plant height and number of leaves, respectively) probably occurred due to the low number of replications (only 3), clearly below the desirable minimum of 10, making difficult a good estimation of errors, mainly of those related to the plots.