Plots were harvested during the senescence period once genotypes reached physiological maturity- when seeds from the main panicle became hard and resistant to pressure (corresponding to a seed moisture content of about 20%).
A 1 m2 area consisting of two central rows was manually harvested in each plot.
- The plant number and height for the harvested area was recorded.
- Plant yield was determined as the total seed weight in one linear meter of two central rows per plot.
>**Yield data are shown as the productivity in t ha−1 at a standard seed moisture content of 20%.**
- The total seed weight was divided by the number of plants sampled to obtain the seed weight per plant.
- The final height was measured for the same plants.
**Seed metrics:**
- 1000 seed weight was determined using a seed counting machine (S-JR, DATA Technologies, Kibbutz Tzora, Israel).
- The proportional weight of a 10 g seed sample retained in sieves of different mesh openings (1.7, 1.4 and 1.18 mm) after 3 min of agitation at 65 rpm.
**Panicle metrics:**
- 50 complete, intact panicles of the central plot rows were imaged with a digital RGB camera (Nikon D3100, 16–55 mm lens)
- Panicle length and maximum width in the images were measured using ImageJ [1]. A ruler was included in each image for calibration purposes.
- The drought tolerance index (DTI) and yield tolerance index (YTI) were calculated for each CLS genotype and cv Regalona as described in Ober et al. and del Pozo et al. [2,3].
References
[1] Schneider, C.A.; Rasband, W.S.; Eliceiri, K.W. NIH image to imagej: 25 years of image analysis. Nat. Meth. 2012, 9, 671–675. \
[2] Ober, E.S.; Clark, C.J.A.; Bloa, M.L.; Royal, A.; Jaggard, K.W.; Pidgeon, J.D. Assessing the genetic resources to improve drought tolerance in sugar beet: Agronomic traits of diverse genotypes under droughted and irrigated conditions. Field Crop. Res. 2004, 90, 213–234.\
[3] del Pozo, A.; Yáñez, A.; Matus, I.A.; Tapia, G.; Castillo, D.; Sanchez-Jardón, L.; Araus, J.L. Physiological traits associated with wheat yield potential and performance under water-stress in a mediterranean environment. Front. Plant Sci. 2016, 7, 987.
