heirloom plants
...that the growing of heirloom plants may help increase the genetic variety of crops?
...that the growing of <b id="mwZQ"><a href="./Heirloom_plant" id="mwZg" rel="mw:WikiLink" title="Heirloom plant">heirloom plants</a></b> may help increase the <a href="./Genetic_variation" id="mwZw" rel="mw:WikiLink" title="Genetic variation">genetic variety</a> of crops?