Characterization of genetic coefficients of durum wheat ( Triticum turgidum L. ssp. durum) ‘Llareta-INIA’ and ‘Corcolén-INIA’

The genetic coefficients, representative of a crop, are necessary to use growth models; in many cases the range of the species is known, but there are no specific values for varieties. Durum wheat ( Triticum turgidum L. ssp. durum ) ‘Llareta- INIA’ and ‘Corcolén-INIA’ were sown under irrigation in the experiment station Antumapu of the Universidad de Chile on 29 June 2007, 19 May 2009, and 15 June 2010 in order to determinate four genetic coefficients: developmental thermal time, phyllochron (PHLN), extinction coefficient (k), and radiation use efficiency (RUE), and to evaluate the performance of these coefficients. Thermal times to anthesis and from anthesis to physiological maturity were 652 and 541° C d, respectively. Two PHLN values were found, 46.6° C d leaf-1 from emergence to fifth leaf and 102.9 ° C d leaf-1 from fifth to eighth leaf. In both cases neither variety nor sowing date was significant. The value of k did not vary among sowing dates for ‘Llareta-INIA’ and was not significantly different from that of ‘Corcolén-INIA’ for normal planting date, due to which a single fit for the two varieties was adjusted, obtaining a value of 0.46. However, ‘Corcolén-INIA’ had a lower value of k for later sowing dates. RUE did not vary between varieties or sowing dates; its estimated value was 2.83 g MJ-1. The evaluation of the coefficients obtained showed coherent results, thus they can be used in model simulations