Radicle emergence and seed imbibition tests as estimators of seed vigour in mexican Pepitilla maize landrace

Seed vigour of Mexican native maize was evaluated in 10 Pepitilla populations (PEP) and three improved varieties by radicle emergence vigour (REVT) and seed imbibition tests, in order to design a plant breeding programme to obtain native varieties with high seed vigour. As part of the REVT, protrusion percentage (PR), radicle emergence (RE), non-germinated seeds (NGS) and radicle length (RL) were measured. Additionally, the imbibition curve and the percentage of testa rupture were recorded. Radicle protrusion in Pepitilla seed lots was 73-94%; for improved varieties, it ranged from 69 to 94%. For 'PEP-2401NS', 'PEP-2402AG', 'PEP-2406GU' and 'PEP-2410RP', RE was equal to PR, so, neither of these genotypes produced a radicle < 2 mm; while, RE in 'V 236P' was 50% lower than PR. In addition, the R 2 of 0.9630 between RE and standard germination suggests that RE can be considered a reliable test to predict maize seed germination. For NGS, 'PEP-2402AG' and 'H-565' showed 6%, and RL in Pepitilla was three times greater than for the improved varieties. After 36 hours imbibition, an improved variety registered the highest water absorption (49.8%), but all Pepitilla landraces showed higher testa rupture. In general, the Pepitilla populations had a high seed-vigour due to the rapid RE and a greater RL.