
TY  - JOUR
A1  - Reader, M. A. 
A1  - Dracup, M. 
A1  - Atkins, C. A. 
T1  - Transient high temperatures during seed growth in narrow-leafed lupin (<emph type="2">Lupinus angustifolius</emph> L.) I. High temperatures reduce seed weight
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 1997
VL  - 48
IS  - 8
SP  - 1169
EP  - 1178
KW  - pod filling, seed filling, yield variability, heat stress, seed composition.
UR  - https://doi.org/10.1071/A97042 
N2  - Highly variable yields are a weakness of narrow-leafed lupins. Yield variability could be caused by many factors, including hot days during seed filling. This paper investigates the effects of 2 hot days at various stages of seed filling in L. angustifoliusL. cv. Merrit. Exposing adequately watered plants to a total of 6 h at 34, 36, or 38&#x02DA;C, compared with 20&#x02DA;C, over 2 consecutive days reduced weight per seed by 4, 8, or 12% at maturity, respectively. The 38&#x02DA;C treatment, applied when seeds averaged 4% of their final weight, also caused significant seed abortion. High temperatures reduced weight per seed at all stages of seed growth, except when seeds were &#60;5-12 mg dry weight (3 and 6% of final seed dry weight, Expts 1 and 2, respectively). The reductions in weight per seed were not associated with reduced assimilate supply because: (a) neither photosynthesis nor leaf longevity were reduced by heat treatment; (b) competing inflorescences and branches were not allowed to develop; (c) the plants produced very large seeds for this cultivar (174-190 mg); and (d) leaves remained green well after the pods had matured. Seed N concentration decreased and fat concentration increased by small, although statistically significant, amounts in response to heat treatment at the last stage of seed development tested (57% of final weight per seed when treated) but not at earlier stages. This study indicates that hot days with pod temperatures as low as 34-36&#x02DA;C during seed development can cause reductions in weight per seed, and hence yields, in narrow-leafed lupin crops. 
ER  -

