INVESTIGADORES
MIRALLES Daniel Julio
artículos
Título:
Floret developmental and survival in wheat plants exposed to contrasting photoperiod and radiation environments during stem elongation
Autor/es:
GONZALEZ, SLAFER Y MIRALLES
Revista:
Functional of Plant Biology
Editorial:
CSIRO
Referencias:
Lugar: Melbourne Australia; Año: 2005 vol. 1 p. 189 - 197
ISSN:
1445-4408
Resumen:
. Wheat breeding has improved yield potential increasing floret survival through higher dry matter
partitioning to the spikes during the stem elongation phase (from terminal spikelet initiation to anthesis). We
studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike
growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments
applied during the stem elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural
photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of
the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation).
Floret survival increased, depending on spikelet position, 1.1¨C2.5 fold under un-shaded v. shaded treatments (both
under NP+0), and 1.3¨C1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments
on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were
associated with duration of floret development within the stem elongation phase (R2 =82%, P<0.0001). Florets
may be classified into three groups: (i) those that were fertile at anthesis under all treatments (mostly the two florets
F1 and F2, proximal to the rachis within the spikelet), (ii) those that reached different stages at anthesis, depending
on treatment, and that contributed differentially to the number of fertile florets at anthesis (mostly the florets F3, F4
and F5, positioned in the middle of the spikelet), and (iii) those that did not contribute to the number of fertile florets
under any treatment (mostly the florets ¡ÝF6). Degeneration of florets in group (ii) was associated with spike growth
at maximum rate, explaining the strong relationship observed between spike dry weight at anthesis and number of
fertile florets. However, degeneration of florets in group (iii) seemed to occur before spike growth at maximum rate.
Survival of florets positioned in the middle of the spikelets could be improved by increasing spike growth through
manipulation of photoperiod sensitivity during stem elongation.