Potential Impacts of Future Climate Changes on Crop Productivity of Cereals and Legumes in Tamil Nadu, India: A Mid-Century Time Slice Approach

Table 2

Genetic coefficients of rice and maize cultivars.

Crop	P1	P2	P2R	P5	P2O	G1	G2	G3	G4	PHINT
Rice: ADT 43	483	—	53.5	348	12	55.8	0.240	1	1	—
Maize: CO(M)H-6	295	0.510	—	840	—	—	635	8.30	—	39.0

Note: P1: thermal time between the emergence of seedling and end of juvenile phase (denoted as degree days over a base temperature of 8°C); P2R: rate to which development (expressed as days) is stalled for each hour rise in photoperiod beyond the longest photoperiod at which development takes at a maximum extent (which is deemed to be 12.5 hours); P5: thermal time from commencement of grain filling (3 to 4 days after flowering) in rice and beginning of silking in maize to attainment of physiological maturity (denoted as degree days over a base temperature of 8°C); P2O: critical photoperiod or the maximum day length (in hours) at which the development happens at a maximum rate. Higher the P2O - developmental rate is decelerated; G1: potential spikelet number coefficient, generally, the value is 55; G2: single grain weight (g) under appropriate growing conditions in rice; maximal number of kernels/ plant in maize; G3: tillering coefficient comparative to IR64 cultivar under optimum conditions (scaler value). In rice, a higher tillering cultivar can have coefficient greater than 1.0; in maize Kernel filling rate at the linear grain filling phase and under ideal conditions (mg/day); G4: temperature resistant coefficient. In normal environment it is usually 1.0; PHINT: phylochron interval; it is give as thermal time (degree days) between subsequent leaf tip appearances.