The investigation of corn kernel qualitycharacteristics during various stages of grain maturity

Although  production  of hybrid corn kernel  is  low,  the value  per unit of yield  is  several   limes greater than that of seed grain.   The production   of hybrid  corn kernel   is  dependent  on timely   harvest  operations    that ensure maximum seed quality  and yield   of inbred parent and hybrid  seed.  The present research was conducted al the Experimental   Farm of the Islamic   Azad University  of Fasa during summer 2000.  The factorial   experiment was designed  based on complete  randomized   block  design   with 3 replications.     The factors were time of seed harvest during  various stages of kernel  maturity  and water deficit.   There were several  harvests from first week to third  week of kernel  maturity. The beginning  of kernel   maturity  was determined  from kernel   growth curve and the end of linear  grow th phase. Water  deficit   consisted   of control,   early and late  water deficit   after pollination. As the aim of this  investigation   was to study of corn kernel  harvest different   times  during   the stages of kernel maturity and the efTects of water deficit  on kernel   quality  characteristics,    kernels  of Sc 704 hybrid parent were seeded. Dry matter weight   and moisture percentage of kernels  and starch and protein percentage  of kernel   was determined   and used for the explanation  of germination  percentage and vigor changes of the kernels.  The results showed that  kernel  kernel  maturity  began from seventh week after pollination   and last  three weeks.   Statistical analysis   of kernel  dry matter weight  showed significant  effect at 5% probability  level  during this three weeks of the  water deficit. Also  early and late  water deficit   reduced kernel  embryo dry matter weight  by average 28.92% and 7.53% respectively   during  kernel    maturity.   Kernel   moisture  percentage  has shown  significant  difference only    during   the  first week of kernel  maturity.  The  germination    percentage  of com  kernels   produced  during kernel   maturity stages was determined. The results  showed that kernel germination  percentage was minimum  in control  treatment during first week of kernel  maturity (27%) and it  was maximum (92%) during the third week of maturity. A linear relationship    was obtained between germination  percentage  and kernel embryo dry matter weight  in control  and late  water deficit  treatments. Seedling dry matter weight  obtained from germination  of the first - week seeds was not affected by water deficit.