Effect of auxin physiological analogues on rapeseed (Brassica napus) cold hardening, seed yield and quality

The effect of the auxin physiological analogues analogues 1-[2-chloroethoxycarbonylmethyl]-4-naphthalenesulfonic acid calcium salt (TA-12) and 1-[2-dimethylaminoethoxicarbonylmethyl]naphthalene chlormethylate (TA-14) TA-14 on different winter rapeseed cultivars were studied with regard to their autumnal growth, cold hardening, accumulation of the stress-protective metabolites proline and saccharide in plant organs: apical bud and root collum, winter survival and productivity formation. The test cultivars were the very early 'Libea' medium-resistant to wintering, the medium-early 'Sunday' resistant to wintering, the medium-early 'Valesca' less than medium resistant to wintering, and the early 'Hornet' (hybrid) tolerant to stress growth conditions. During the period of cold hardening in natural field conditions, the test compounds TA-12 (2 mM) and TA-14 (4 mM), applied to different winter rapeseed cultivars at the 4th-5th leaf stage, stimulate accumulation proline and saccharides (sucrose and glucose) in the root collum and apical bud tissues, influence plants acclimation to cold, overwintering and productivity formation. Compounds TA-12 and especially TA-14 produced a stable effect on seed and crude fat yield in cvs. 'Hornet', 'Sunday' and 'Libea'. The genotypic peculiarities of a cultivar and the meteorological conditions of the plant vegetation period were the factors that mostly determined fatty acid content in seed oil.