Thomson: At ICARDA a large number of parameters have been used to select barley varieties with improved straw quality. If such parameters as polyphenolics are added to the selection criteria there is a danger of making the task of plant breeders too complicated.
Capper: One approach could be to use appropriate parameters to calibrate a near infrared-reflectance spectrophotometer, which could subsequently be used to screen a larger number of samples.
McAllan: Near-infrared-reflectance spectro-photometry has been used at an early stage in the breeding and selection of high-lysine barley, but effective calibration requires analysis of 30 to 50 samples. Nuclear magnetic resonance is an alternative promising technique.
Onim: I believe it would not be worthwhile to start selecting for straw quality at an early stage in the breeding process. It would be more productive to work with released varieties or to study the straw quality of promising material. The primary objective should be to increase grain yields. Selection for straw quality may detract from the primary focus of increasing grain yield.
Jenkins: If the plant breeder is presented with a large number of characteristics to select for there is less likelihood of producing a variety at the end of the day. It may be possible to select for a single important factor if the animal nutritionists can identify a reliable indicator of feeding value.
Reed: We hope to present data in the following sessions of the workshop which will show the possibility of identifying crop residues with superior quality. However I agree that routine screening may be impracticable and work may be most appropriate towards the end of the breeding process. The first step is to examine each species and identify factors limiting nutritive value.
Schildkamp: The conflict between straw and grain may be less apparent at the farm level. If straw has a lower nutritive value the farmer will have to feed other materials to his animals. In the Ethiopian highlands there is a trend towards growing forage which, by taking up land that could be devoted to cereals, reduces grain production.
Said: A compromise might be for the plant breeder to produce two types of varieties. Varieties that respond to a high level of inputs could be introduced for farmers interested in grain production; for the farmer interested in both straw and grain, dual-purpose varieties might be bred. However I also support the view that evaluating gene banks may not be productive.
Gupta: I believe it may be necessary to go back to gene banks, but this will depend upon particular circumstances. Where food is in short supply the first priority must be for food grains, but where there is a surplus of food grain but a shortage of feed for livestock more emphasis should be placed on crop residues.
Khush: Higher grain yields need not necessarily be achieved at the cost of lower crop residue value. Since farmers apply more nitrogen fertiliser to higher yielding varieties this may increase the nitrogen content of the residues. In other circumstances, where there is a grain surplus this might be used to supplement he crop residues.
Ørskov: I have screened over 100 varieties of different crops and found no correlation between grain yield and straw quality.
Thomson: It is clear that nutritionists still have a lot to do to identify factors affecting the nutritive value of crop residues but there is clearly a strong desire to work with plant breeders.
