Effect of naphthaleneacetic acid on root and plant growth and yield of ten irrigated wheat genotypes

Plant growth regulators (PGRs), such as 1-naphthaleneacetic acid (NAA), gibberellins, cytokinins, abscisic acid, and ethylene have become commercialized in some countries to increase the productivity of field crops and to fortify the value of horticultural crops. However, very limited research has been conducted in Bangladesh on root growth, plant biomass and yield of wheat (Triticum aestivum L.) using NAA. In this context, an experiment was conducted over two consecutive seasons, from November to April, in the research field of the Wheat Research Center (WRC) (under Old Himalayan Piedmont Plain), Dinajpur-Bangladesh. Treatments consisted of the application of 25 mg/l NAA in five temporal regimes: 1) NAA applied at 20, 35 and 50 days after emergence (DAS); 2) NAA applied at 20 and 35 DAS; 3) NAA applied at 20 and 50 DAS; 4) NAA applied at 35 and 50 DAS; 5) a control (without NAA). Treatments were applied to 10 irrigated spring wheat genotypes i.e., ‘Kanchan’, ‘Protiva’, ‘Surov’, ‘Gourov’, ‘BAW 944’, ‘BAW 953’, ‘BAW 994’, ‘Akbar’, ‘Agrhani’ and ‘Sonalika’, and arranged in a split-plot design, namely as five NAA treatments as the main plots and 10 wheat genotypes as the sub-plots. In both seasons, data on root fresh and dry weight, root length, total plant dry biomass (TDM), grain yield (GY) and yield attributes of wheat were significantly (p?0.05) influenced by the NAA application regime and genotype. However, maximum root fresh and dry weight and longest roots were recorded in treatment 2 for ‘Gourav’. Maximum TDM was recorded at 40 and 50 DAS for ‘BAW 944’ in treatment 3. Significantly similar and maximum TDM at 60 DAS was found for ‘Kanchan’ and ‘Sourav’ in treatment 1 and at 70 DAS for ‘Sourav’ in treatment 2. ‘BAW 994’, ‘BAW 953’ and ‘Agrahani’ produced significantly similar and maximum number of spikelets spike-1 in treatment 2. ‘BAW 944’ and ‘BAW 953’ showed significantly similar 1000-grain weight in treatment 3 while smallest grain size was obtained in ‘BAW 953’ in the control treatment. ‘BAW 953’ produced highest GY in treatment 1, and was statistically similar to ‘BAW 994’ and ‘Protiva’ after the application of treatments 2 and 4. Therefore, the application of NAA at 20, 35 and 50 DAS in all genotypes was more effective (i.e., better root growth and yield) than the control plot. Among the 10 tested genotypes, ‘BAW 953’ and ‘BAW 994’ responded most to NAA. © 2019, Pakistan Botanical Society. All rights reserved.Bangladesh Agricultural Research InstituteThis research was conducted as part of a national research program of the Wheat Research Centre, BARI, Dinajpur, with the financial support of BARI from the annual research budgets

Biplot Yield Analysis of Heat-Tolerant Spring Wheat Genotypes (Triticum Aestivum L.) in Multiple Growing Environments

It is important to identify and develop stable wheat varieties that can grow under heat stress. This important issue was addressed in Bangladesh using six wheat genotypes, including three existing elite cultivars (‘BARI Gom 26’, ‘BARI Gom 27’, ‘BARI Gom 28’) and three advanced lines (‘BAW 1130’, ‘BAW 1138’, ‘BAW 1140’). Six sowing dates, namely early sowing (ES) (10 November), optimum sowing (OS) (20 November), slightly late sowing (SLS) (30 November), late sowing (LS) (10 December), very late sowing (VLS) (20 December) and extremely late sowing (ELS) (30 December) were assessed over two years in four locations, representative of the diversity in Bangladesh’s agro-ecological zones. In a split plot design, sowing dates were allocated as main plots and genotypes as subplots. A GGE biplot analysis was applied to identify heat tolerance and to select and recommend genotypes for cultivation in heat-prone zones. All tested genotypes gave greatest grain yield (GY) after OS, followed by SLS, ES and LS, while VLS and ELS gave smallest GY. When GY and the correlations between GY and stress tolerance indices were considered, ‘BAW 1140’, ‘BARI Gom 28’ and ‘BARI Gom26’ performed best under heat stress, regardless of location or sowing date. In contrast, ‘BARI Gom 27’ and ‘BAW 1130’ were susceptible to heat stress in all locations in both years. Ranking of genotypes and environments using GGE biplot analysis for yield stability showed ‘BAW1140’ to be most stable, followed by ‘BARI Gom 28’ and ‘BARI Gom 26’. Wheat sown on November 20 resulted in highest GY but that sown on December 30 resulted in lowest GY in both years. In conclusion, ‘BAW 1140’, ‘BARI Gom 28’ and ‘BARI Gom 26’ are the recommended wheat genotypes for use under prevailing conditions in Bangladesh

Productivity, nutrient balance, and economics of monsoon rice under different nutrient management practices in two agro-ecological zones of Bangladesh

Inherently poor soil fertility and non-adoption of fertilizer recommendations based on soil test and yield targets by farmers limit the productivity and profitability from monsoon rice in Bangladesh and much of South Asia. In the Level Barind Tract (LBT; AEZ-25) and the High Ganges River Floodplain (HGR; AEZ-11) agro-ecological zones (AEZs) of Bangladesh, monsoon (aman/kharif) season transplanted rainfed rice (known as T. aman rice) is grown in large areas after maize, wheat and/or mungbeans, with residues of each crop removed from the field after grain harvest. This results in lower grain yield and lower profits in these AEZs as compared with other AEZs. Nutrient management, based on soil test, yield targets, or integrated use of inorganics and organics for each AEZ together with retention of crop residue, has the potential to increase rice yield, reduce production cost and increase income. With this hypothesis, this study was conducted to determine the optimum nutrient management practices for achieving higher yield, maintaining apparent soil nutrient balance, and obtaining high profits from monsoon rice. Twelve nutrient management options were evaluated, of which the first six were: (i) 80-16-44-12-2 kg ha-1 of N, P, K, S, Zn respectively for a high yield goal (T1; ‘HYG’); (ii) 56-12-32-8- 1.5 kg ha-1 respectively for a medium yield goal (T2; ‘MYG’); (iii) 65-13-32-9-2 kg ha-1 respectively plus 5 t ha-1 cowdung as integrated plant nutrient management system (T3, ‘IPNS’); (iv) 67-14-41-9-2 kg ha-1 respectively as a soil test-based fertilizer management strategy (T4; ‘STB’); (v) 40-9-11-0-0 kg ha-1 respectively as per farmers’ practice (T5; ‘FP’) and (vi) 0-0-0-0-0 kg ha-1 as a control (T6; ‘CON’). The remaining six treatments were the same as above but each also included the crop residue incorporation (CRI), i.e., (vii) T7, ‘HYG+CRI’; (viii) T8, ‘MYG+CRI’; (ix) T9, ‘IPNS+CRI’; (x) T10, ‘STB+CRI’; (xi) T11 ‘FP’+CRI’; and (xii) T12, ‘CON+CRI’. In both AEZs, STB plus CRI resulted in the highest rice yield (p≤0.05) followed by ‘STB’ and ‘IPNS+CRI’. In comparison with ‘FP’ and ‘CON’, each without CRI, balances were positive (p≤0.05) for P, S, Zn and B but were negative for N and K in ‘HYG’, ‘MYG’, ‘IPNS’ and ‘STB’ with or without CRI. In both AEZS, STB nutrient management had the highest (p≤0.05) net returns (526 & 487 US$ ha-1, respectively), highest benefit cost ratio (BCR; 3.54 & 3.36) and highest marginal benefit cost ratio (MBCR; 10.47 & 10.19). These were followed by STB+CRI’ and ‘IPNS’, while they were lowest (p≤0.05) for CON and FP. We recommend that nutrient application, based on soil test with incorporation of mungbean residue, followed by IPNS, could be the best strategies for achieving high yield, improving soil fertility and for fetching a higher profit from monsoon rice in Bangladesh and similar soils and growing environments of South Asia