Breeding of String Bean cv Nan 1

Abstract

The breeding programme for string bean cv Nan 1 (YBR 8-1) was carried out since 1989.  Local variety from Nong Khi and Phichit provinces were used as a parental material of YB 5.  The YB 5 was then crossed with the siring bean from Nan province and six imbred lines namely YBR 5-1, YBR 5-3, YBR 8-1, YBW 8-2 including YBR 8-1 and them the string bean cv Nan 1 was obtained.  After hybridization, pure line selection methods were applied during the programme until F 8.  In 1999 varietals trial for six inbred lines mentioned were conducted at the Phichit Horticulture Research Centre and at the NanOil-palm Research Centre to compare and evaluate with commercial variety.  Result showed that YBR 5-2 and YBR 8-1 lines had good crop performance in term of a better crop yield both in Nan and Phichit conditions.  Ingeneral, YBR 5-2  yields was significantly higher than a commercial control veriety however, when the experiment was conducted for panel taste, YBR 8-1 also showed better qualities in terms of its taste, crispy, strength and charming red colour pod.  The YBR 8-1 prominently showed high pigments of anthocyanine which was 10.33 mg./100 g. of fresh pod and gave higher yield at an average of  3,290 kg/ rai, which was 27.9 % higher than the control or commercial variety during very late growing season or beginning of the winter.  Although on-farm trial, YBR 8-1 was not shown numerically a better crop yield, but also was very well comparable marketing to the commercial string bean due to attractive distinct colour which had been different from the commercial control vareity.