Composition and Flowering Quality of Cacahuacintle Maize Populations from the High Valleys of Mexico.

Cacahuacintle is one of the maize types with great demand for pozole preparation; however, little is known about the variation in chemical composition and flowered grain quality among populations. Physicochemical characteristics, flowered grain quality, pasting properties, and starch microstructure were evaluated in 33 populations of Cacahuacintle maize collected in Valles Altos, Mexico. The seeds samples of corn were obtained in 2017 from local farmers in the states of Mexico, Puebla, and Tlaxcala. Results were analyzed under a completely randomized design, and the ANOVA, Tukey test, and principal components were obtained. The ANOVA showed significance (p ≤ 0.05) in 18 of the 22 variables evaluated. The TE-6, AM-7, and CA-6 populations were outstanding for the good quality of their protein, pasting viscosity, and flowered grain quality. Nine populations collected in Calimaya, estate of Mexico, and Serdan Valley, state of Puebla, presented excellent physical, pasting, and flowery grain characteristics, with reduced protein content and lysine and tryptophan values typical of maize with normal endosperm. The softness of the endosperm grain, starch microstructural, and pasting characteristics of Cacahuacintle maize populations have a fundamental role in reducing the time and increasing the flowered grain volume, properties that were different from those observed in the Chalqueño, included as dent maize check. Variations in grain quality among Cacahuacintle maize populations is an important genetic resource for the improvement of the nutritional and flowering quality of Cacahuacintle maize.

Pectobacterium carotovorum subsp. brasiliense Causes Soft Rot and Death of Neobuxbaumia tetetzo in Zapotitlan Salinas Valley, Puebla, Mexico.

Neobuxbaumia tetetzo (Coulter) Backeberg (tetecho) is a columnar cactus endemic to Mexico. Tetecho plants, flowers, fruits, and seeds play an important role in the semiarid ecosystem, as they serve as a refuge and food for insects, bats, and birds, and are widely used by ethnic groups since pre-Hispanic times. Tetecho is affected by a soft rot that damages the whole plant and causes its fall and disintegration. Eight bacterial colonies of similar morphology were isolated from plants showing soft rot and inoculated in healthy tetecho plants, reproducing typical symptoms of soft rot 9 days after inoculation. Ten representative isolates were selected for phenotypic and genetic identification using 16s rDNA, IGS 16S-23S rDNA, and rpoS genes and for pathogenicity tests on several members of the cactus family and other plants. Based on the results, these bacterial isolates were identified as Pectobacterium carotovorum subsp. brasiliense. Inoculation of this bacteria caused soft rot in different cacti, fruits, leaves, and roots of other plants. This is the first report of the subspecies brasiliense of P. carotovorum causing soft rot and death in cacti in the world and the first report of this subspecies in Mexico.