A climatological study on minimum temperature and its relationship with wheat yield at Ludhiana

Thirty years data (1975–2005) on minimum temperature of Ludhiana, located in the central plain region of Punjab state at an altitude of 247 m above msl for the month of December to February were collected and classified into various groups for interpretation. Results showed that the lowest and the highest minimum temperature recorded during the study period were -0.6 and 20.8°C respectively in the month of January during different years. The Coefficient of Variation varied from 35–46 per cent. Persistence in minimum temperature for five days was found to be maximum varied from 36.2 to 46.2 per cent. Analysis indicated that maximum number of cold waves occurred during February. Among the months, wheat yield was found to be more correlated with minimum temperature during February than during January & December. The coefficient of determination was highest for February (24%) followed by January (21%) and December (15%).