ABSTRACT
Cherry tomatoes are usually cultivated under greenhouse which is out of the reach of the marginal farmers. Due to unavailability of microclimatic and biochemical data in cherry tomato, meagre yield is obtained at open field conditions. Since the microclimatic factors and growing environment have immense influence on yield and quality attributes of any crop, this experiment was aimed to study the correlation of microclimate with the yield and quality contributing traits of eighteen genetically diverse genotypes of cherry tomato at open field trained on trellis and under naturally ventilated polyhouse conditions. In the given study, under open conditions, mean canopy temperature in morning at 7 a.m. (15.3-19.4°C) showed highly significant positive correlation with total yield, whereas total yield possessed highly significant negative association with the mean mid-day (12 noon) canopy temperature and mean mid-day soil temperature above 25°C. In poly house condition, total yield reflected significant negative correlation with morning mean canopy temperature (24.6°C) and mid-day mean canopy temperature (25.8-26°C), whereas total yield was negatively correlated with morning and mid-day mean soil temperature when the temperature was above 20.7°C. Among biochemical parameters, lycopene and beta-carotene content increased with mean canopy temperature at 19.5°C and further decreased above 21.5°C, however TSS increased with increase in mean canopy temperature from 15 to 25°C and decreased beyond 30°C temperature.
ABSTRACT
Aim: A study was conducted to develop a new approach of non-stress baseline and evaluate different approach of determining non stress baseline for Crop Water Stress Index (CWSI).Methodology: To observe maximum and minimum canopy temperature, two plots with three replications were maintained at fully stress (no irrigation) and no stress (fully irrigated) conditions, respectively. Portable weather station with data logger was installed at the middle of field to record continuous data at half an hour interval. Gypsum block soil moisture sensor were buried at 20 cm interval up to 100 cm and connected with data logger. Infrared radiometer was used to measure canopy temperature. Results: The evaluation was based on five statistical indicators; correlation coefficient (R2), root mean square error (RMSE), mean absolute error (MAE), mean bias error (MBE) and Wilmot index of agreement (d). It was found that new regression base line performed better than other existing approaches. The calculated value of RMSE, MAE, MBE, d and R2 were 0.65, 0.51, 0.02, 0.79 and 0.83, respectively, for new baseline approach. Interpretation: The newly developed multiple regression equation (incorporating three weather parameters (Rn, VPD and u) and two crop growth parameters (h and CC)) helped to reduce error in the calculation of non-stress baseline for wheat crop in humid subtropical climate
ABSTRACT
A rice variety Jyothi (PTB 39) is a red kernelled with bold grain, popular in the region of Kerala, India used in the study. Plants were grown in pots under three different conditions, natural solar UV-B conditions, UV-B excluded condition using UV-B filters and supplemental UV-B using UV-B lamps along with ambient solar radiation. During the study period, UV-B radiation was in the range of 1.30 to 3.58 Wm2 which affected the productivity of the crop under open solar condition. A decrease in morphological traits like plant height, number of tillers, flag leaf angle and increase in leaf thickness were observed. Physiological parameters, leaf gas exchange parameters and biochemical constituents such as chlorophyll content also recorded less value under high UV-B condition along with the high content of protective compounds such as flavonoid content, catalase and PAL activity. The phenophases of the crop were also delayed by 4-5 days under UV-B radiation exposed conditions. All these negative impacts of UV-B radiation on crop leads to restricted filling of grain, lesser harvest index and grain development leading to a decrease in yield and yield attributing characters.