ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Pre- and Postharvest Factors Influencing the Development of Stress Cracking and Other Quality Attributes of Maize Grains

Kim TH, Opara LU, Hampton JG, Hardacre AK

Institute of Technology and Engineering, Massey University, Palmerston North / NZ Seed Technology Institute, Lincoln University, Lincoln / Crop & Food Research Institute, Palmerston North, New Zealand

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บทคัดย่อ

The effects of several preharvest ( hybrids, nitrogen, harvest grain moisture contents ) and postharvest drying factors ( drying temperature and relative cooling rate ) on physical attributes and stress cracking in maize grain were investigated . Grain hardness ratio increased in all three hybrids with increasing nitrogen fertiliser application, but the effects of nitrogen on grain hardness and drying rates were small . Stress cracking incidence and the stress crack index ( SCI ) were significantly affected by the main effects of hybrid, nitrogen, harvest moisture, drying temperature and cooling rate and various interactions among them . There were differences among hybrids on type and incidence of stress cracking, irrespective of preharvest and postharvest . As drying temperature increased from 50 o C to 80 o C, the percentage of multiple and checked stress cracking increased, but stress cracking did not differ between a drying temperature of 60 o C and 70 o C . As cooling rate reduced from 1.11 to 0.23 o C / o C / minute, the number of sound grains ( non stress - cracked grains ) significantly increased . These results indicated that hybrid ( genotype ) had greater influence than preharvest factors on drying rate and stress cracking in maize grain .