IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
capítulos de libros
Título:
Variability on photoperiod responses in Argentinean wheat cultivars differing in length of crop cycle
Autor/es:
3. MIRALLES D.J., M.V. SPINEDI, L.G. ABELEDO & D. ABELLEYRA
Libro:
Wheat Production in stressed environments. (Proceedings of the 7th. International Wheat Conference).
Editorial:
Springer
Referencias:
Lugar: Dordrecht, Netherlands; Año: 2007; p. 599 - 610
Resumen:
Crop cycle in cereals is associated with a sequence of phenological events controlled by environmental factors, mainly temperature and photoperiod. The duration of developmental phases has an important impact on yield. Thereby, to understand how and at what extend both genotype and environment affect the timing of phenological events is of paramount importance for both (i) calculating the risk of climatic conditions during phenological phases (eg. frost damage on heading) and (ii) organizing in advance management practices (eg. fertilization during tillering). This study was designed to determine the genotypic variability on the duration of phenological phases of a wide range of  Facultative Argentinean wheat cultivars exposed to different sowing dates. The experiment was carried out during 2004 in the experimental field of Dep. Plant Production FA UBA without water and nutritional stress. Pest and diseases were prevented or controlled. The study consisted on a factorial combination of 20 commercial facultative wheat cultivars differing on the length of the whole cycle (10 classified as early maturity and 10 classified as late maturity) and six sowing dates (8 June, 26 June, 19 July, 9 August, 18 August and 18 September). Treatments were arranged in a randomized block design with two replicates. Developmental stages of emergence (E), first visible node (N1), flag leaf emergence (FL), heading (H) and anthesis (An) were recorded when 50% of the plants reached the stage. Results showed that 3 out of 20 cultivars evidenced vernalization requirements. Cultivars classified as early and late maturity showed different photoperiod sensitivity during the E-An phase. The average photoperiod sensitivity was -74 and -165 ºC d h-1 for early and late maturity groups, respectively. Within groups, sensitivity ranged between -25 and -180 ºC d h-1 for the early maturity, while the late maturity group ranged from -100 to -230 ºC d h-1. Intrinsic earliness did not show significant differences between groups, i.e. 829 and 907 ºC d, for early and late maturity, respectively. Similarly, a slight variation in this trait was found among cultivars within each group. Critical photoperiod, i.e when the rate of development reaches the maximum value, was 13.4 hs without significant differences between groups. In addition, no-significant difference was found in phyllochron (ranging between between 94 and-112 ºC d) between early and late maturity cultivars.