Track: Industry Practices and Solutions

Abstract

Seed Certification prerequisites trade and marketing of crop seed varieties within and across countries or Global Regions. A Seed Lot can only be certified if it meets minimum quality of genetic and physical purity standards as enshrined in Certification Schemes of Certifying Authority or Agency of respective Organisations, Countries, or   Regions. The quality standards set may vary considerably across Seed Certification Schemes. Meeting of genetic purity standards in maize seed production requires Distance and Time Isolation husbandry techniques in the separation of seed production fields from sources of foreign pollen in neighbouring contaminant maize fields. These two Seed field Isolation techniques however require minimisation in response to ever rising pressure on land and tight turn around cropping schedules in farms. Essias Michael Kok (1985), with help of Ephrame Kudzaishe Havazvidi, showed that minimum Distance Isolation set for Certification of maize seed crops could be reduced to 122 metres provided that the protected maize seed crop is planted on the leeward side of the potential contaminant maize crop and that the synchronisation (or nicking ) of pollen shed in the male parent of the seed maize crop with silking period in the female parent of the protected seed maize crop is perfect. Time Isolation technique obviates distance separation of seed fields from potential contaminant maize crops and furthermore removes wind current challenges which may reduce effectiveness of Distance Isolation. Ephrame Kudzaishe Havazvidi (1989) derived Time Isolation Formulae and quantified Safety Factors in the formulae to ensure reliability in their effectiveness. He derived Time Isolation Constants specific to the genetic constitution of female parents of the different seed maize crops i.e. inbred females, sisterline cross females and single cross females, respectively. Corrective measures to conform excessive genetic contamination of seed maize to certification standards set can be taken using algorithms derived by the Author (unpublished). The principle behind Ephrame Kudzaishe Havazvidi’s algorithms lies in the mixing or blending of inferior quantities of seed lots with specified quantities of seed lots containing much higher genetic or physical quantity fractions than those stipulated in Seed Certification Schemes in question. These algorithms can also be applied in other Industrial Blending or Stoichiometric formulations.