Plant Heritage chairman Alan Titchmarsh warned that the trade was in danger of promoting new plants and letting old ones "slip away" (HW, 16 July).
Peter Seabrook responded that old varieties of tomatoes, for instance, had disappeared because they were tasteless, yielded poorly and got diseases.
Garden Organic horticulture director Bob Sherman said (HW, 30 July): "It is very rare that we see major improvement in plants and, when we do, they deserve praise. Peter mentions the tomato 'Red Alert' - a great variety that, in my opinion, has yet to be surpassed 20 years on."
Hansord said of old tomatoes varieties: "They tell you they are good but the flavour is terrible and so is the disease resistance. There is a tendency for that particularly with tomatoes. There are some poor tomatoes out there. Some don't yield, some are susceptible to disease and not nice to eat.
"We have gone for tried and tested varieties but you have to be careful what you encourage people to do. We don't want our customers to be disappointed. With grow your own currently trendy, we don't want to disappoint gardeners. We want to make them more successful."
T&M vegetable product manager Colin Randel said in potatoes, the term heritage usually referred to pre-1950s varieties but it can mean anything in vegetables.
He added that some old varieties lacked the flavour, yield, disease-resistance and colour of newer ones, but some, such as 'Scarlet Emperor' runner bean were better than modern varieties.