Different irrigation methods and water stress effects on potato yield and yield components

This research was conducted during the spring seasons of 2000 and 2002 in Hatay province located in the East Mediterranean Region of Turkey. The research investigated the effects of two drip irrigation methods and four different water stress levels on potato yield and yield components. The surface drip (SD) and subsurface drip (SSD) irrigation methods were used. The levels were full irrigation (I100), 66% of full irrigation (I66), 33% of full irrigation (I33) and un-irrigated (I0) treatments. Five and three irrigation were applied in 2000 and 2002 early potato growing seasons, respectively. Total irrigation amount changed from 102 to 302 mm and from 88 to 268 mm in 2000 and 2002, respectively. Seasonal evapotranspiration changed between 226 and 473 mm and 166 and 391 mm in 2000 and 2002, respectively. SD and SSD irrigation methods did not result in a significant difference on yield. However, SD method has more advantages than SSD method, which has difficulties in replacement and higher system cost. Irrigation levels resulted in significant difference in both years on yield and its components. Water stress significantly affected the yield and yield parameters of early potato production. Water deficiency more than 33% of the irrigation requirement could not be suggested. [1]

Path Analysis of Rice Yield and Yield Components as Affected by Seeding Rate

Understanding relationships among rice (Oryza sativa L.) yield and yield components (panicle density, filled grain per panicle, unfilled grain per panicle, and grain weight) is critical to utilizing these relationships effectively. Interrelationships among rice yield and yield components for direct-seeded rice cultural systems using path-coefficient analysis that describes a priori cause-and-effect relationships have not been shown. Our objective was to study direct-seeded rice yield and yield component relationships as affected by seeding rates using path-coefficient analysis. ‘Lemont’, a semidwarf rice, was seeded at 43, 85, 128, 170, and 213 kg ha−1 in four environments between 1986 and 1988. The seeding rate by environment interaction was nonsignificant for all traits, indicating stable performance across environments. As seeding rates increased, panicle density increased significantly, and filled grain per panicle decreased significantly, an indication of the compensatory nature between these two traits. Higher panicle densities at the lower seeding rates were due in part to increased tillering of the rice plants. Path-coefficient analysis revealed that panicle density had the largest positive direct effect on rice yield, even at low seeding rates where filled grain per panicle increased to compensate for decreased panicle density. Direct effects for filled grain per panicle and grain weight were of secondary and/or tertiary importance in determining rice yield. Unfilled grain per panicle had negligible effects on rice yield. To achieve optimum rice yields and grain quality in a direct-seeded cultural system, adequate panicle density per unit area of uniform maturity must be achieved. [2]

Deficit irrigation and nitrogen effects on maize in a Sahelian environment: I. Grain yield and yield components

Maize (Zea mays L.) is an important food crop for irrigated perimeters of the African Sahel. Large demand and limited water availability often results in deficit irrigation. Increasing cost of two controllable production inputs-water and nitrogen (N) further demands their efficient use. In a 2-year field study, maize was grown under five irrigation treatments, providing deficit irrigation during vegetative and reproductive periods at five N levels on a Tropudalph clay loam soil. The purpose of this study was to (i) determine effect of timing and frequency of deficit irrigation and N on maize yield and yield components and, (ii) evaluate the interaction of deficit irrigation and N on evapotranspiration (ET) and water use efficiency (WUE) under a semi-arid Sahelian environment.

When two deficit irrigations during the vegetative period were imposed, grain yield was numerically reduced by 11.1 and 6.6% in 1996/1997 and 1997/1998 seasons, respectively. When deficit irrigation occurred during the vegetative stage and early reproductive stage, significant yield reductions of 22.6 and 26.4% were found for the respective seasons. Imposition of six or eight deficit irrigations during vegetative and reproductive phases reduced grain yield by up to 52% over all N levels. Yield reductions were associated with reduction in kernel numbers and to a lesser extent, kernel weight. Thus, grain yield reduction was nearly proportional to duration of deficit irrigation imposed during the season.[3]

Genetic Variability and Inter Relationship between Yield and Yield Components in Some Rice Genotypes

The study was conducted at the Sudan University of Science and Technology; College of Agricultural Studies, Shambat farm during the season 2009/10 to study genetic variability and correlation between yields, yield components in some rice genotypes. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Seven characters were measured including yield, yield components. Phenotypic () and genotypic () variances, phenotypic (PCV) % and genotypic (GCV) %, coefficients of variation were estimated. Phenotypic and genotypic correlation between characters was determined. The results showed that there were highly significant differences (p≤0.01) between the most of the characters under study except for percentage of unfilled grains per panicle (%). The highest values of phenotypic and genotypic variance were recorded by yield kgha-1 Also grain yield was attained the highest values of phenotypic and genotypic coefficients of variation. Positive phenotypic and genotypic correlation coefficient was detected between grain yield and number of filled grains per panicle, harvest index, panicle length and number of grains per panicle. The present study revealed that there was highly genetic variability among the tested genotypes, indicating that it could be used for further improvement in rice breeding. [4]

Yield and Yield Components of Sweet Potato as Influenced by Plant Density: In Adami Tulu Jido Kombolcha District, Central Rift Valley of Ethiopia

Two best performing, morphologically different sweet potato varieties namely, Balella and Bareda, were used to determine optimum spacing between plants and rows in central rift valley of Ethiopia by participating different influential factors from the commencement of the activity. The results indicated that total tuber yield of Balella (644 ±105 q ha-1) performed better with spacing 20 cm x 80 cm than the rest of the treatments i.e., 20 cm x 60 cm (590 ±104 q ha-1) and 50 x 60 cm (522 ±137 q ha-1). But the net marketable yield obtained at spacing combination of 20 cm x 60 cm (590±104 q ha-1) was by far better being followed by 20 cm x 80 cm and 50 cm x 60 cm that gave average yield of 583±82 q ha-1 and 463±93 q ha-1, respectively. Correlation matrix of dependent variables resulted that green top weight was significantly correlated with total and marketable root yield (0.887** and 0.846**, respectively). This indicated that variation in total root yield and marketable root yield was accounted by the linear function of total green top yield r2=78.7 % and r2=71.6%, respectively. For Bareda, 20 cm x 60 cm spacing gave total yield of 409 ± 257 q ha-1 followed by 20 cm x100 cm and 30 cm x 60 cm that gave yield of 347 ±139 q ha-1 and 294 ± 63 q ha-1, respectively. The correlation of green top and total root yield obtained for Bareda was strong and positive (r=0.689**). [5]

Reference

[1] Onder, S., Caliskan, M.E., Onder, D. and Caliskan, S., 2005. Different irrigation methods and water stress effects on potato yield and yield components. Agricultural water management, 73(1), pp.73-86.

[2] Gravois, K.A. and Helms, R.S., 1992. Path analysis of rice yield and yield components as affected by seeding rate. Agronomy Journal, 84(1), pp.1-4.

[3] Pandey, R.K., Maranville, J.W. and Admou, A., 2000. Deficit irrigation and nitrogen effects on maize in a Sahelian environment: I. Grain yield and yield components. Agricultural water management, 46(1), pp.1-13.

[4] Idris, A.E., Justin, F.J., Dagash, Y.M.I. and Abuali, A.I., 2012. Genetic variability and inter relationship between yield and yield components in some rice genotypes. Journal of Experimental Agriculture International, pp.233-239.

[5] Abdissa, T., Chali, A., Tolessa, K., Tadese, F. and Awas, G., 2011. Yield and yield components of sweet potato as influenced by plant density: In Adami Tulu Jido Kombolcha district, Central Rift Valley of Ethiopia. Journal of Experimental Agriculture International, pp.40-48.