Seed Yield Stability of Okra as Influenced by Planting Date

Abstract

Fifteen selected okra varieties consisting of ten newly-developed lines and five established varieties were evaluated for stability of seed yields in eight different environments i.e. several monthly plantings for three consecutive years. Seed yield data were analyzed to determine the effectiveness of using different planting dates in seed yield trials of new okra varieties. The wide ranges of environmental indices ( -10.8 to 24.4) and seed yield (2.7 to 38.0 g plant"') indicated significant variation between the environments even though the trials were conducted at the same location. A regression method of stability analysis showed that the mean differences between environments, the varieties and their interactions were highly significant. These results suggest that where limited resources prevent the use of several locations, different dates of planting for two or more years could be used to evaluate okra varieties for seed yield without losing much information on their relative ranking.The interaction of genetic and environmental effects on crop performance, usually referred to as the genotype x environment (G x E) interaction, is of great concern to plant breeders seeking to develop new crop varieties. The presence of G X E interactions causes difficulty in getting a reliable estimate of hentability and predicting the rate of genetic progress under selection for a particular character.The common practice adopted by breeders to minimize the biases resulting from G X E interaction is to subject the new varieties to multilocation performance tests (Al I ARU 1961;Al EARD and BRAUSIIAW 1964) for several years. This helps to identify varieties which give superior performance over a wide range of environments. However, the scarcity of research funds in the developing countries has reduced the possibility of conducting such tests in an adequate number of locations and years. The cheaper alternative is the unilocation test under different micro-environmental conditions created by varying plant density, fertilizer rates and planting dates. This paper reports the results of seed yield trials involving 2 to 3 monthly plantings of fifteen okra varieties, conducted at

Studies of factors effecting an improvement of seed production and seed quality in okra, seed hardness and methods of overcoming this problem

“…Ariyo (1987) evaluated sowing 15 okra genotypes in 5 different environments and found a significant environmental effect on plant height and performance. Similarly, in a study of 25 genotypes in West Africa, the season of planting was found to have a positive effect on pod yield via its influence on plant height, the number of branches and pod number (Alake et al, 2012), a result supported by Adetunji and Chheda (1989), Franco and Ortegn (1997) and Singh et al (1986). Apart from its effect on plant growth, sowing time may also affect seed quality because this characteristic is highly dependent on the climatic conditions during seed maturation.…”

“…In most cases, however, sowing times differed greatly (e.g. different seasons) (Alake et al, 2012;Adetunji and Chheda, 1989;Franco and Ortega, 1997;Singh et al, 1986), whereas here the sowing times were only 20 days apart.…”

Μελέτη της επίδρασης διαφόρων παραγόντων που επηρεάζουν την μετασυλλεκτική συμπεριφορά και ποιότητα τηςμπάμιας (Hibiscus esculentus)

“…Ζ επαγσγή ησλ αλζνθφξσλ νθζαικψλ θαη ε άλζεζε θαζπζηεξνχλ ζε πςειέο ζεξκνθξαζίεο εκέξαο (>35ºC), ελψ πςειή ζεξκνθξαζία λχρηαο (>27ºC) κπνξεί λα πξνθαιέζεη αχμεζε ηνπ χςνπο ησλ θπηψλ ζηηο πεξηζζφηεξεο πνηθηιίεο (Tenga and Ormrod 1985). Θεξκνθξαζίεο >20ºC πξνσζνχλ ηελ άλζεζε, φκσο ζε ζεξκνθξαζίεο >42ºC κπνξεί λα ζπκβεί πηψζε αλζέσλ (Singh et al 1988, Adetunji andChheda 1989).…”