Understanding the chapatti making attributes of the Indian wheats – II: The rheological basis

The concept of good chapati varies from individual to individual and depends mainly on the rheological properties of the dough used to prepare the chapaties. The research project was largely built around two type of plant meterials, the tall traditional cultivars of the pre-dwarfing era, and three backcross recombinant populations (BC1F5 generation) C 273/PBW 343//PBW 343 (70 lines), C 306/PBW 534//PBW 534 (70 lines) and C 518/PBW 343//PBW 343 (80 lines). Association of traits studied with chapati score in set of cultivars and genetic stocks Starch pasting characteristics showed mild negative correlation with chapati quality, which is again contrasting, to the requirements of bread making. The correlations were not consistent over years possibly due to environmental factor (temperature, rainfall, fertilizer and irrigations etc.) and due to change in the constitution of the set. Similarly mixographic traits showed negative association chapati making quality. The correlations which prevail in the populations carry much greater weight as these have persisted over several rounds of recombination and are likely to reflect under lying causes of superior chapati quality. As various components of chapati quality would be disassembled, the relative levels of correlations for individual traits would be uncovered. Among the starch pasting characteristics, final viscosity and setback were consistently negatively associated with the chapati making quality. In case of the mixographic traits, mixing tolerance index is negatively associated whereas rate of dough development has consistent positive correlation with chapati quality.

Understanding the chapati making attributes of the Indian wheats – I: The physico-chemical basis

The research project was largely built around the tall traditional cultivars of the pre-dwarfing era, which were known to excel for chapati quality. These included C 306, C 518 and C 273. The few cultivars that had emanated from crosses of these superior chapati quality wheats with dwarf wheats formed another important component of this set and included WG 357, PBW 175, PBW 154, PBW 226, Lok 1 among others. Asecond set of materials, three backcross recombinant populations (BC1F5 generation) derived from C 273/PBW 343//PBW 343 (70 lines), C 306/PBW 534//PBW 534 (70 lines) and C 518/PBW 343//PBW 343 (80 lines) were also studied to arrive at some conclusion. Various physico-chemical characters(Grain appearance score,Grain hardness,Test weight,1000-grain weight,Yellow berry,Moisture content,Protein content,Gluten content, Gluten index, Sedimentation value, Phenol Test, Carotenoids, Sugar content, Diastatic activity, Falling Number) and chapati-makingscores were evaluated. Grain hardness seems to have a clear role in chapati quality with a correlation coefficient of 0.34, 0.35 and 0.17 observed in different recombinant populations.More consistent correlation was found for grain appearance ranging from 0.26 to 0.36 in the populations.Consistent high positive correlations have showed up for diastase activity, which ranged from 0.32 to 0.46.This consistent behaviour is a strong evidence for the role of this trait in chapati making quality.Diastase activity emerges as a more consistent and stronger contributor to chapati making quality. Phenol score may not serve as a suitable indicator of chapati quality.