Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. II. Soyabean (Glycine Max)

Abstract

Eleven genotypes of soyabean (Glycine max) of tropical, sub-tropical and temperate origin and one accession of G. soja were grown in six locations in Australia during 1986-88, and at one location in Australia and two in Taiwan during 1989-91. Dates of sowing were varied within and among locations so as to expose plants to as many as 32 environments of widely different diurnal temperature and daylength. Times from sowing to flowering (/) were recorded, from which rates of progress towards flowering (1//) were calculated. These derived data were then related to mean pre-flowering values of temperature (T) and photoperiod (P) using a threeplane linear model developed from controlled environment data. Among genotypes, mean values of/ varied between 24-49 d and between 134-291 d in the most-and least-inductive environments, respectively. These differences were associated with variations in P from about 11 to 16 h d~', in daily mean maximum temperatures from about 17° to 36°C, in daily mean minimum temperatures from about 5° to 25°C, and in T from about 11° to 30°C, that is, a very wide range of photothermal regimes. The relations of l / / t o T and P can be described in photoperiod-insensitive genotypes by a thermal plane defined by two constants, a and />, and additionally by a photothermal plane defined by three constants, a', V and c'', in the more numerous photoperiod-sensitive genotypes. If photoperiod-sensitive genotypes are grown in sufficiently long days then a third photoperiod and temperature-insensitive plane is exposed, defined by a constant, d'\ this plane indicates the maximum delay in flowering of which the Present addresses: §Queensland Department of Primary Industries, PO Box 591, Ayr, Queensland 4807, Australia; "11 Edward Crescent, Byford, Western Australia 6201. 254 R. J. SUMMERFIELD et al.genotype is capable. The constants a', b', c' and d' define the delay in flowering caused by photoperiod-sensitivity genes. The two intercepts between the three planes define, respectively, the critical photoperiod, P c , above which increase in daylength delays flowering, and the ceiling photoperiod, P ce , above which there is no further delay. The values of the six constants for any genotype can be estimated from observations of/in several natural environments. Comparisons between years in Australia and between Australia and Taiwan show that these genotypic constants can predict \/f, and so the time taken to flower, given data on latitude, sowing date and daily values of maximum and minimum air temperatures. This model is more accurate than an alternative logistic model; we also believe that all six constants in the three-plane rate model described here have biological meaning. They indicate separate genetic control of flowering responses to P and T and could form a rational basis for the genetic characterization and analysis of these responses in the soyabean germplasm. Pronostico del momento defloration II RESUMENSe cultivaron once genotipos de poroto de soja (Glyane max) de origen tropical, subtropical y te...

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

“…The critical photoperiod for flowering in a cowpea genotype from Uganda (' TVu 1188 ') has been found to range from 16n0 h d − " at 15 mC to 11n5 h d − " at 25 mC . Reports on soya bean are contradictory : in a controlled environment study, critical photoperiods for flowering in eight cultivars have been found to increase with temperature (Hadley et al, 1984), while in field experiments, the critical photoperiods for flowering in nine different soya bean genotypes decreased with temperature (Summerfield et al, 1993). In the latter study, critical photoperiods of 12n6 to 13n6 h d − " at 20 mC and 11n7 to 13n3 h d − " at 25 mC have been found.…”

“…The ceiling photoperiod for the rate from flowering to podding in ' Tiga Nicuru ' decreased from 13n95 h d − " at 22 mC to 13n07 h d − " at 26 mC (Table 4). Summerfield et al (1993) found that ceiling photoperiods for the rate to flowering in soya bean increased with temperature. The difference is due to the fact that the parameter b # in the photothermal response plane of ' Tiga Nicuru ' has a negative value (1\( pkf ) decreases with temperature), while this parameter has a positive value (development rate increasing with temperature) for the soya bean genotypes used by Summerfield et al (1993).…”

“…Summerfield et al (1993) found that ceiling photoperiods for the rate to flowering in soya bean increased with temperature. The difference is due to the fact that the parameter b # in the photothermal response plane of ' Tiga Nicuru ' has a negative value (1\( pkf ) decreases with temperature), while this parameter has a positive value (development rate increasing with temperature) for the soya bean genotypes used by Summerfield et al (1993). This means that the photothermal plane of ' Tiga Nicuru ' is tilted differently than the photothermal plane in Fig.…”

“…; soya bean [Glycine max (L.) Merr.] (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).…”

Phenological variation among Israeli populations of Cicer judaicum Boiss.

“…A similar approach was adopted in the comprehensive study of the photo-thermal control of flowering in grain legumes (e.g. Summerfield et al 1995).…”