Physiological Characterization of Cold Tolerant and Susceptible Pigeon Pea [Cajanus cajan (L.) Millsp.] Genotypes

Background: The cold stress adversely affects the growth, survival and reproductive capacity of plants if the minimum temperature falls below 5°C. Information’s regarding cold stress and its impact on morphological characters, physio-biochemical constituents and yield attributes in cold tolerant and susceptible pigeon pea genotypes are very limited. Keeping the above facts in to consideration, the experiments were conducted. Methods: Field experiments were conducted during 2018-19 and 2019-20 with 34 genotypes of pigeon pea including checks (NDA-1, Bahar, IPA203, NDA-2, MAL-13, ICP2275, IPACT-2, MA-6, IPACT-3, IPACT-24, Rajendra Arhar, IPA15F, Dholi-D, JBT46/27, IPACT-6, IPACT-14, IPAD1-17, IPAC 68, IPACT 22, ICPL 7035 IPA19-101, IPA19-102, IPA19-103, IPA19-104, IPA19-105, IPA19-106, IPA19-107, IPA19-108, IPA19-109, IPA19-110, IPA19-111, IPA19-112, IPA19-113, IPA19-114) in RBD at ICAR-IIPR, Kanpur. Morphological and yield Characters including plant height, scoring of cold injury in exposed plants and Number of flower drop and pod set during the cold period in tagged plants were recorded. In biochemical/ crop efficiency parameters viz: Nitrogen balance index, chlorophyll, flavonols, anthocyanin’s and NDVI were measured. The photosynthetic rate, stomatal conductance, and transpiration rate were measured at the pod formation stage. Anti-oxidant enzymes activity was assayed as per standard methods. Meteorological observations during Cold stress were recorded. Result: Based on flower/pod drop and retention the genotypes like IPA 15F, Dholi dwarf, JBT46/27, IPACT-6, IPACT-14, IPAC-1-17, IPACT-68, IPACT-22, IPA 19-101, IPA 19-102, IPA 19-103, IPA 19-104, IPA 19-105, IPA 19-107, IPA 19-108, IPA 19-109, IPA 19-110, IPA 19-111 and IPA 19-113 were found susceptible to cold stress and retaining an average 51.67 % flowers/pods. Genotypes like NDA-2, MAL-13, ICP2275, IPACT-2, MA-6, IPACT-3, IPACT-24, Rajendra arhar, IPA19-106, IPA19-112 and IPA19-114 have retained more than an average of 67.48% flowers/pods are considered tolerant to cold stress. Amongst the tolerant group NDA-2, MAL-13, ICP2275, IPACT-2, IPA19-106, IPA19-112 retained the flower/pod more than the average of check genotypes (67.57%). Biochemical/plant efficiency parameters were superior in tolerant group over susceptible group.