Field evaluation of chlorophyll meter for screening groundnut (Arachis hypogeae L.) genotypes tolerant to iron-deficiency chlorosis

摘要

Groundnut, an important oilseed crop of India, frequently suffers from iron-deficiency chlorosis which may become so severe that the entire plant becomes yellow, papery-white., and may even die resulting in severe yield losses. As groundnut genotypes differ in their ability to utilize iron, selection of Fe-efficient genotypes which can tolerate Fe-deficiency chlorosis is the solution to this problem. Presently no field instrument is used to measure the intensity of chlorosis and only visual diagnosis, using visual chlorotic rating (VCR) and chlorophyll content determination method is widely used for selecting genotypes tolerant to iron-deficiency chlorosis in the field. Therefore, the present investigation was carried out to explore the possibility of using a chlorophyll meter (SPAD) for rapid and in situ screening of groundnut genotypes for their tolerance to iron chlorosis. The study showed that correlation between SPAD readings and chlorophyll content was positive and highly significant with r value of 0.94** for chlorophyll a, 0.90** for chlorophyll b, and 0.93** for total chlorophyll. This has clearly indicated a closer relationship of these traits with SPAD reading, i.e. higher the SPAD reading, higher will be the chlorophyll pigments and vice versa. The regression lines showed these that these variables have a linear relationship with each other. On the basis of the linear relationship regression equations were developed from which it is possible to predict the chlorophyll content and VCR of the leaves. Thus the chlorophyll meter is an efficient and speedy equipment for screening genotypes for their tolerance to iron-deficiency chlorosis. [References: 10]