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Photosynthetic assimilation of 14 CO 2 and fate of 14 C‐labelled photosynthate in winter wheat ( Triticum aestivum ) near‐isoclines differing in alleles at the Rht 1 and Rht 2 reduced‐height loci *
Author(s) -
KIYOMOTO R. K.,
GENT M. P. N.
Publication year - 1989
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1989.tb06794.x
Subject(s) - photosynthesis , anthesis , biology , grain yield , winter wheat , yield (engineering) , dry matter , cultivar , horticulture , biomass (ecology) , agronomy , botany , zoology , materials science , metallurgy
Summary The mechanism by which reduced‐height genes, Rht 1 and Rht 2 influence yield and harvest index (HI) were investigated in dwarf (D, Rht 1 Rht 2 ), semidwarf (SD‐1 and SD‐2, Rht 1 rht 2 and rht 1 Rht 2 , respectively), and tall (T, rht 1 rht 2 ) near‐isogenic lines (isolines) derived from winter wheat cv. Burt. Dry matter accumulation, yield, and assimilation, distribution, and retention of 14 C label from photosynthetic assimilation of 14 CO 2 , was followed in field‐grown plants in Connecticut, USA. The relationships among the isolines were similar over the two years of study. The tall isoline ranked highest in grain yield and biomass, but had a small HI; SD‐1 was similar to T in yield and biomass, but had the largest HI; SD‐2 was similar to SD‐1 in HI, but its yield and biomass were less than SD‐1 and T; and D yielded the least grain and biomass and had a small HI similar to T. Following photosynthetic assimilation of 14 CO 2 during grain filling, the distribution of 14 C in ears at maturity was similar for SD‐1, SD‐2, and T. When labelled shortly after anthesis or late in grain filling, the distribution of 14 C to the mature ear of D was less than that for other isolines. At maturity D also retained the smallest amount of the radioactivity initially assimilated. The low yield and HI of D may be related to its inability to retain photosynthate and distribute it to the grain. The SD‐1, SD‐2, and T isolines did not differ in retention at maturity of 14 C in the whole plant. When labelled shortly after anthesis, stems of T retained more 14 C, which may represent a tendency to sequester more photosynthate in its stems that would reduce its HI at maturity. In contrast, the yield of SD‐2 was limited by photosynthetic capacity.