Rapid Identification for Drought Resistance of Wheat Using Near-infrared Diffuse Reflectance Spectroscopy

[Objective] This study aimed to establish an identification system for drought-resistance in wheat by using near-infrared diffuse reflectance spectroscopy. [Method] In 2006-2007, 36 wheat varieties with different drought resistance were selected and were classified according to their drought resistance grades determined by the Technical Specification of Identification and Evaluation for Drought Resistance in Wheat （GB/T 21127-2007）. In addition, the harvested wheat seed samples were spectrally analyzed with FOSS NIRSystems5000 near-infrared spectrum analyzer for grain quality （full spectrum analyzer） and then the forecasted regression equations were established. [Result] After the establishment of a database and validation, dis- criminated functions were obtained. The determination coefficient （RSQ） and coeffi- cients of determination for cross validation （1-VR） in the discriminant function built with seed samples from water stress area were 0.846 0 and 0.781 8, respectively, which indicated that the consistency between drought resistance and spectral charac- teristics in wheat varieties was good, and there was high correlation between the near-infrared diffuse reflectance spectra of seeds and the drought resistance in wheat. [Conclusiou] Under water stress condition, it is feasible to establish a conve- nient, rapid and no-damage identification system for the drought resistance in wheat by using the near-infrared diffuse reflectance spectrum technique to scan wheat seeds.

Method of Distinguishing Hydrologic Drought for Water Supply System

It is very common to design water supply system to adjust runoff. Thus it will not meet the practical needs if only the hydrologic drought in natural basin is studied. In practice the natural water balance and water deficits must be researched, i. e. . the adjusting effects of the water supply sys- tem such as a reservoir should be considered, and the drought event be distinguished according to the special system. The problem of drought identification under adjusted runoff was investigated in this study. By considering water transfer during different periods, a method to distinguish hydrologic drought for the water supply system was developed, and a standard drought severity index SWDSI was proposed. The method has been applied in Pan Jiakou water supply system in China. From 1953 to 1997,a total of 14 hydrologic droughts were identified in the water supply system, among which there were 3 severe droughts, 6 moderate droughts and 5 light droughts. The results are in good agreement with the historic drought records.

Characterization of Drought and Its Assessment over Sindh,Pakistan During 1951-2010

Drought is one of the complex meteorological disasters affecting water resources, agriculture, livestock, and socioeconomic patterns of a region. Although drought prediction is difficult, it can be monitored based on climatological information. In this study, we provide high spatiotemporal resolution drought climatology, using observational, gridded precipitation data （0.5°×0.5°） from the Global Precipitation Climatological Center and soil moisture data from the Climate Prediction Center for the 60-yr period 1951-2010. The standardized precipitation index （SPI） based on a fitted Gamma distribution and Run method has been calculated from the regional drought identification model （ReDIM） for 3, 6, 9, 12, and 24 months. The results show strong temporal correlations among anomalies of precipitation, soil moisture, and SPI. Analysis of long-term precipitation data reveals that the drought vulnerability concentrates on monsoon season （July- September）, which contributes 72.4% and 82.1% of the annual precipitation in northern and southern Sindh, respectively. Annual and seasonal analyses show no significant changes in the observed precipitation. The category classification criteria are defined to monitor/forecast drought in the selected area. Further analysis identifies two longest episodes of drought, i.e., 1972 1974 and 2000 2002, while 1969, 1974, 1987, and 2002 are found to be the most severe historical drought years. A drought hazard map of Sindh was developed, in which 10 districts are recognized as highly vulnerable to drought. This study helps to explain the time, duration, intensity, and frequency of meteorological droughts over Sindh as well as its neighboring regions, and provides useful information to disaster management agencies and forecasters for assessing both the regional vulnerabilitv of drought and its seasonal predictability in Pakistan.