Field evaluation of a model of photothermal flowering responses in a world lentil collection

Abstract

A model to predict flowering time in diverse lentil genotypes grown under widely different photothermal conditions was developed in controlled environments. The present study evaluated that model with a world germ plasm collection of 369 accessions using two field environments in Syria and two in Pakistan. Photoperiod alone accounted for 69% of the variance in 1/f, the reciprocal of time (d) from sowing to flower. In contrast, temperature alone did not account for a significant proportion of variation in flowering time due to the exposure of plants to supra-optimal temperatures in the late-sown Syrian trial. With the model mean pre-flowering values of photoperiod and temperature combined additively to account for 90.3% of the variance of 1/f over accessions. The correlation of field-derived estimates of temperature sensitivity of accessions to glass-house-derived estimates was significant at P = 0.05, but the equivalent correlation for estimates of photoperiodic sensitivity was higher at P < 0.01. Flowering in the field was better measured as time from sowing to 50% plants in flower rather than time to first bloom or its node number. Dissemination of the lentil crop following domestication in West Asia to the lower latitudes such as Ethiopia and India has depended on selection for intrinsic earliness and reduced sensitivity to photoperiod. Movement from West Asia to the higher latitudes accompanied by spring sowing has resulted in a modest reduction in photoperiod sensitivity and an increase in temperature sensitivity.

Abiotic Stresses

“…These were the Levantine group (Egypt, Jordan, Lebanon and Syria), the northern group (Greece, Iran, Turkey, USSR, Chile), the Indian subcontinent group and the Ethiopian group. Erskine et al (1994b) later found that the dissemination of lentil around the world has resulted in the selection of different regionally specific balances between photoperiod and temperature for the control of flowering. These regionally specific flowering responses provide the basis for adaptation to the climatic variables of an environment for which abiotic and biotic constraints can be evaluated and addressed.…”

“…The clustering of traits that define the phenological adaptation of lentil to an ecological environment indicated that local environments have been important in the evolution of the species (Erskine et al 1989). The dissemination of lentil into new environments has thus caused selection for different regionally specific balances between photoperiod and temperature for the control of flowering (Erskine et al 1994b). For example, cultivated lentil spread from West Asia to the Indo-Gangetic plain around 2,000 BC .…”

Rates of Progress towards Flowering and Podding in Bambara Groundnut (Vigna subterranea) as a Function of Temperature and Photoperiod

“…(Hadley et al, 1984 ;Summerfield et al, 1993) ; mungbean [Vigna radiata (L.) Wilczek] (Ellis et al, 1994 b); chickpea (Cicer arietinum L.) (Roberts, Hadley and Summerfield, 1985 ;Ellis et al, 1994 c) ; lentil (Lens culinaris Medic.) Erskine et al, 1994) ; and faba bean (Vicia faba L.) (Ellis, Summerfield and Roberts, 1990).…”

Plant genetic adaptedness to climatic and edaphic environment

“…Lentils and wheat are two of many possible examples. After domestication, the dissemination of the lentil crop from West Asia to lower latitudes depended on selection for intrinsic earliness and reduced sensitivity to photoperiod ; and to higher latitudes on a modest reduction in photoperiod sensitivity and an increase in temperature sensitivity (Erskine et al ., 1994) . In fact, earliness is one of the most important adaptations in some harsh environments .…”