Abstract
Maize (Zea mays L.) is widely cultivated worldwide for food, feed, and fuel uses. Maize forage has become a valuable feed material and its feed value depends on its nutritional value, and more specifically on its digestibility and ingestibility, i.e. the dry matter voluntarily intake by the animal. This value is linked to the speed at which the feed is reduced to small particles in the mouth, and is therefore impacted both by the animal (chewing quality, etc.) and by the characteristics of the forage, in particular its friability. This characteristic should be related to both the composition of the stalks and their organization at the tissue level, these two parameters being conditioned by genetic and environmental factors. The maize stalk friability could be successfully assessed by the milling behavior, and the particle size of chopped maize fragments (obtained just after the harvest) should be probably relevant. The objective of this study are (i) to characterize the particle size distribution of centimeter-sized maize fragments using imaging and image analysis approaches, and (ii) to assess the effect of a change in composition or tissue structure on stalk friability. At first a macro imaging bench was developed and validated on reference samples, including the development of the methodology to assess particle size based on images of bulk fragments Then a collection of maize stalk samples (4 inbred line, 2 hybrids) grown in different water stresses conditions will be characterized both by imaging and for their friability.