"Adaptability Pattern for short duration wheat under environmental dynamics".

Abstract

The third and final phase of the project work titl?d "Yield co-efficients and stability of wheat varieties planted at different seeding depths and environments" was laid out in RCB design at Peshawar, Pirsabak, and Jamra locations covering the wide range of environment. The experiment was consisted of four replications each of which having eight treatments with plot size of 3 x 5 mat each site. Wheat varieties included were Kaghan-93, Pirsabak-85, Khyber-87, and Pirsabak-91 and the seeding depths were 5 and 9 cm to assess the agronomic effectiveness and stability performances of varieties for different agronomic characters. Statistically significant results were obtained in yield and yield components due to locations, varieties but seed depths did not affect agronomic traits except plant height. Only locations X varieties interaction could affect productive tillers m-2, 1000-grain weight, grain yield, and seed growth rate while all other possible interactions could not affect agronomic parameters. Locations responded statistically differently. Pirsabak location was more responsive over Peshawar and Jamra in emergence (110.61 seedlings/m2), tiller m-2 (207.50), 1000-grain weight (41.22 g), biomass (8.825 t/ha), grain yield (3.283 t/ha), harvest index (39.75%), and in grains/spike (38.28) while Peshawar location showed maximum plant height of 96.86 cm. Only plant height was affected due to seeding depths with plants of 95.01 cm tall in shallow seeded crop (5 cm). Emergence (plants m-2), tillers m-2, 1000-grain weight (gm), biomass (t/ha), grain yield (t/ha), harvest index, and grain/spike were recorded higher in Khyber-87 among all the varieties planted at different environments and seeding depths while variety Pirsabak-85 could only show superior performance for plant height by attaining taller plants of 96.36 cm among the varieties. Tillers m-2, 1000-grain weight (g), grain yield (t/ha) were observed significant and recorded maximum

of 208.30, 43.38, and 3.576 respectively in variety Khyber- 78 at Pirsabak location under L XV interaction whereas

oyher parameters remained unaffected due to locations x varieties interaction. Through out the study, all other interactions were noted statistically non- significant in all agronomic traits. Seed fill duration and seed growth rate are the two important phys1ological parameters which help greatly in assessing the growth pattern of varieties under existing hostile environment and are oftenly considered key parameters in determining the yield efficacy of varieties. Among the locations, Pirsabak and Peshawar were more responsive to seed fill duration and seed growth rate by

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showing 48.38 days to filling and 0.878 mg/day/grain respectively while Khyber-87 was the superior variety for seed fill duration (51.25 days) and seed growth rate (0.871 mg/day/grain). Nll the possible interaction could not affect both the parameters except L XV interaction in seed growth rate by showing maximum of 0.915 mg/grain/day in Khyber-87 at Pirsabak location. Correlation and regression studies of different agronomic traits showed significant and positive relationship with grain yield except plant height which indicated negative and significant correlation. In regression study, emergence, tillers, grain weight, biomass, harvest index, and grains/spike with grain yield revealed that each unit increment in these parameters increased yield proportionately except plant height which indicated that increase in height would result decrease in grain yield at the same rate. The stability performances of different wheat varieties for different agronomic characters in the present investigation were generally discussed on the basis of Eberhart and Russell, (1966) model and Finlay and Wilkinson (1963) method of characterizing varieties stable or unstable. Stability parameters included were seed yield ranking, regression coefficient (bi) and mean square deviation from linear regression which demonstrated an interesting approach towards adaptability of varieties for certain cha r ac t e r.s , In the present study, varieties Pirsabak-85 and Khyber-87 for grain yield, Kaghan-93, Khyber-87 and Pirsabak-91 for tillers/m2 were categorized themselves as stable varieties as their bi approaching 1. Varieties Kaghan-93, and Pirsabak-91 for seed yield,

Pirsabak-85 for tillers/m2 and all varieties except Khyber- 87 for the both 1000-grain weight and seed growth rate could

be placed below average stable varieties (bi> 1), thereby showing increasing adaptability only in high yielding environment while Khyber-87 only for grain weight and seed growth rate characterized itself as above average stable variety as its bl approaching zero reflecting the situation of well performance only in low yielding environment or under unfavourable environmental conditions.