Collection HIGHLIGHTS Sugarcane hybrids with improved IWUE have greater scope in sugarcane agriculture as irrigation water is getting scarce.  Among sugarcane hybrids, Co 8371 registered high mean water productivity of 4.18 kg m -3 , followed by Co 85019(3.92 kg m -3 ), while in I 2 , six hybrids had significantly higher water productivity (Co 85019, Co 0212, Co 86249, Co 10026, Co 0218 and Co V92102) above 4 kg m -3 .  Deficit irrigation scheduling (irrigation at recommended interval, with 50% crop evapotranspiration replacement) appears to be far more useful than reducing frequency as well as quantity of irrigation water alone. Hybrid mean water productivity was 3.2, 2.7, and 2.1 kg m -3 in I 0 , I 1 , and I 2 , respectively.ABSTRACT. The escalating deficit rainfall scenario in India indicates that drought is a recurrent phenomenon associated with tropical sugarcane farming, and the availability of irrigation water for sugarcane cultivation will be much less in coming years. To meet the challenge of limited and costly water supply, tropical sugarcane growers will have to find ways of increasing the efficiency of irrigation to maintain high cane yields. More efficient irrigation systems, accurate irrigation scheduling, and the right choice of sugarcane hybrids are potential means of increasing irrigation water use efficiency (IWUE), water productivity (WP), and global water security. With the objective of optimizing irrigation water use, a field experiment evaluating the physiological efficiency of commercial sugarcane hybrids for WP in a sandy clay soil under water-limited conditions was conducted during 2016-2017 at the ICAR-Sugarcane Breeding Institute in Coimbatore, India. The replicated field experiment was laid out in split-plot design with three irrigation levels as the main plot and 33 sugarcane hybrids as subplots. The prevailing climatic conditions during the experiment represented a tropical wet and dry climate, with the wet season lasting from October to December due to the northeast monsoon. The results showed that full irrigation at recommended intervals with 100% crop evapotranspiration (ET) replacement (I 0 ) produced significantly higher cane yield than deficit irrigation at recommended intervals with 50% crop ET replacement (I 1 ) and skipping alternate irrigations with 50% crop ET replacement (I 2 ). The deficit irrigation treatments (I 1 and I 2 ) had declines in cane yield of 41.2% and 56.4%, respectively. IWUE was similar in I 0 and I 1 , while I 2 had reduced IWUE by 23%. WP was significantly influenced by irrigation level; reduction in irrigation water reduced WP by 17.5% and 36.3% in I 1 and I 2 compared to I 0 . Among sugarcane hybrids, Co 85019, Co 13006, Co 10026, Co 99004, CoLk 8102, Co 86249, Co 8371, Co 94008, and Co 95020 yielded higher than the genotypic mean under both deficit irrigation treatments, suggesting their usefulness in deficit irrigation strategies. Sugarcane hybrids with high WP can play a pivotal role in sustaining sugarcane productivity and can reduce the larg...

Collection HIGHLIGHTS `Significant reductions in canopy temperature depression (CTD), chlorophyll fluorescence (F v /F m ), SPAD index, and leaf rolling index were observed under limited irrigation during the grand growth stage of sugarcane.  This study highlights the significance of CTD and F v /F m as useful physiological tools for selecting sugarcane clones suitable for production under water-limited conditions.  Clones Co 10026, Co 13006, Co 85019, Co 62175, Co 86010, and Co 1148 performed better under limited irrigation, and these clones can reduce the amount of irrigation water required for sugarcane production, ensuring water security.ABSTRACT. Sugarcane is one the most important commercial crops in India and globally. The annual water requirement for sugarcane ranges from about 1000 to 2900 mm, and this variation mainly depends on the agro-ecological conditions, cultivation practices, and crop cycle. In a changing climate, the delay or failure of monsoons will have a direct effect on the water available for irrigation in India. Given these constraints, sustaining sugarcane production is challenging. The ICAR-Sugarcane Breeding Institute (ICAR-SBI) in Coimbatore, India, has developed sugarcane genotypes that are resilient to drought stress. To study the role of physiological traits in identifying sugarcane varieties suitable for water-limited conditions, an experiment was conducted at ICAR-SBI with sugarcane clones in field conditions using irrigation at 100% cumulative pan evaporation (I 0 ) and with 50% reductions in the volume and frequency of irrigation (I 2 ). Physiological traits, including canopy temperature depression (CTD), chlorophyll fluorescence (F v /F m ), soil plant analysis development (SPAD) index, leaf rolling index (LRI), and cane yield, were recorded for sugarcane clones grown under I 0 and I 2 . Significant reductions of 85. 9%, 15.4%, 4.9%, 44.9%, and 56.0%, respectively, in CTD, F v /F m , SPAD index, LRI, and cane yield were found for water-limited conditions (I 2 ) compared to I 0 . F v /F m showed a decreasing trend in I 2 compared to I 0 and also showed a significant positive correlation (r = 0.43) with cane yield. CTD varied significantly between the two treatments and also showed a significant positive correlation with cane yield (r = 0.45). Both F v /F m and CTD are adaptive traits for waterlimited conditions and are useful for screening sugarcane clones suitable for water-limited conditions. Clones Co 10026, Co 13006, Co 85019, Co 62175, and Co 86010 had superior cane yields under water-limited conditions (I 2 ) and better physiological traits. Water deficit is one of the most critical abiotic stresses that affect sugarcane productivity. By growing clones that are water use efficient (Co 10026, Co 13006, Co 85019, Co 62175, and Co 86010), the irrigation water requirement can be reduced for sugarcane production in India. In addition, new sugarcane clones can be developed for waterlimited conditions by using the identified clones in breeding programs for water use efficienc...

Maize crop requires number of macro-nutrients and micro-nutrients for its growth and development. Nitrogen is one of the key nutrients needed for crop production; however, it is the most mobile and volatile and mainly exhausted nutrients due to its ability to exist in unusual forms and its easy leach ability. Lack of knowledge among the maize growers about the consequences of irrational use of water and nitrogen is mainly responsible for low water use efficiency and nitrogen use efficiency at field level. A field experiment was conducted during kharif, 2018 and rabi, 2019 under maize crop at the field irrigation laboratory, Department of Soil and Water Engineering, Dr. N. T. R. College of Agricultural Engineering, Bapatla, Guntur district of Andhra Pradesh State, India. The rainfall received during crop growing period of kharif 2018 was 303.4 mm and 69.1 mm during rabi, 2018-19. The initial soil physical and chemical properties of the experiment site were calculated. The inline drip irrigation system was designed in split pot for the experiment with three irrigation levels (main plots) namely I 1 = 0.6 of the crop evapotranspiration, I 2 = 0.8 of the crop evapotranspiration and I 3 =1.0 of the crop evapotranspiration and four nitrogen levels ( sub plots) namely N 1 = Drip fertigation with 80% of recommended dose of nitrogen (CF), N 2 = Drip fertigation with 100% of recommended dose of nitrogen (CF), N 3 = Drip fertigation with 120% of recommended dose of nitrogen (CF) and N 4 = No drip fertigation (manual application) with 100% of recommended dose of nitrogen (CF) with three replications. The amount of crop water requirement of maize was estimated with computer software CROPWAT (v 8.0). The dry matter production (DMP) and nitrogen use efficiency (NUF) of maize were estimated for both the seasons. The results shown that during kharif 2018 the highest value of DMP was found in I 3 treatment (399.22 kg ha -1 ) followed by I 2 and I 1 treatments (392.93 and 381.90 kg ha -1 ). During rabi 2018-19, the value of DMP was found in I 3 treatment (574.62 kg ha -1 ) followed by I 2 and I 1 treatments (565.29 and 446.38 kg ha -1 ). The highest NUE of 32.88 kg ha -1 mm -1 was obtained in I 2 N 1 treatment during kharif 2018. During rabi 2018-19, the highest NUE of 32.85 kg ha -1 mm -1 was in I 2 N 2 . The lowest NUE of 21.35 and 22.36 kg ha -1 mm -1 was obtained in I 1 N 3 treatment during kharif 2018 and rabi 2018-19.