Path Coefficient Analysis of Correlation Between Stress and Barley Yield Components1
- W. F. Campbell2,
- R. J. Wagenet2,
- A. F. Bamatraf3 and
- D. L. Turner2
Water and fertility management practices are needed that will ensure economic crop production on irrigated lands in semi-arid regions with extremes in drought and salinity. Barley, Hordeum vulgare L., was used as an indicator crop to evaluate the interactive effects of fertilizer (N and P), salinity, and irrigation management on crop yields. Greenhouse experiments with four replications were imposed on a nonsaline nongypsiferous Hunting silty clay loam soil (Aquic Ustifluvent). Nitrogen (0, 112, 224 or 448 kg N/ha) and F (0, 45 or 90 kg P/ha) were applied as urea and calcium superphosphate prior to planting. Six to eight seeds were planted in 576 pots and irrigated with tap water until the plants reached the two-leaf stage, at which time they were thinned to two plants per pot. Salinity (ECW = 0.5, 1.5> 4.5, or 13.5 mmhos/cm) and water (irrigation interval of 2, 4, or 8 days) management treatments were then initiated. Data were collected on yield components and environmental factors.
Regression coefficients (r3) on interactions were low, indicating that a small proportion of the total yield variability was accounted for by the various variables. However, water quality and quantity and N fertilizer interactions exhibited significant (P < 0.01) effects on yield components. Moreover, a negative yield response was produced by decreasing irrigation frequency and increasing water salinity. According to the correlation coefficients, three yield components (main heads, tiller heads, and floret abortion) had comparable effects on yield. In contrast, the path coefficients analysis attributed yield differences to direct and indirect influences of various parameters. Where correlation analysis simply measured mutual association between the various parameters and variables, the path analysis measured the relative importance of each. Although results indicated reduction in yield parameters, if managed correctly, moderately saline water can be used to obtain reasonable (but not maximum) yields. Where maximum yield decisions have to be made, however, better quality land and water should be used for crop production.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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