Many methods have been proposed for the identification of seed maturity, and almost all of them need to be performed after seed harvest. In this study, a real-time quantitative method that can be performed during seed development was used by integrating multiple-capsule traits using a high-throughput screening (HTS) technique. Capsule color, shape, and density parameters can reflect seed development and maturity. During seed development, we observed a fast decrease in color parameters (R, G, and B) and water content, as well as an increase in temperature sensitivity; an initial rise followed by decline in shape parameters [length, width, minimum circumscribed circle (MCC) diameter, area] was also observed; as well as irregular differentiation of density parameters of the capsules. Correlation analysis showed a significant relationship between seed maturity and capsule color, as well as its shape parameters (Table 1). In sum, our data demonstrate that that three-dimensional (3D) phenotypic platform can be used to differentiate seed maturity by quantitative evaluating multiple-capsule traits, which is a quantitative method for determining the maturity of seed while still growing in the fruit of the mother plant.
Zhenhua Li, Yiling Liu and RenXiang Liu
Xiaomeng Li, Rangjin Xie, Zhenhua Lu and Zhiqin Zhou
Citrus species are among the most important fruit trees in the world and have a long cultivation history. However, until now, the exact genetic origins of cultivated Citrus such as sweet orange (Citrus sinensis), lemon (C. limon), and grapefruit (C. paradisi) have remained unidentified. In the present study, amplified fragment length polymorphism (AFLP) fingerprints, nuclear internal transcribed spacer (ITS), and three plastid DNA regions (psbH – petB, trnL – trnF, and trnS - trnG) of 30 accessions of the cultivated citrus and their putative wild ancestors were analyzed in an attempt to identify their paternal and maternal origins. Molecular phylogenetic trees were constructed based on the AFLP data, and chloroplast DNA and ITS sequences using the genus Poncirus as the outgroup. Our results indicated that bergamot (C. aurantifolia) and lemon were derived from citron (C. medica) and sour orange (C. aurantium), and grapefruit was a hybrid that originated from a cross between pummelo (C. grandis) and sweet orange. Rough lemon (C. limon) was probable as a parent of rangpur lime (C. limonia) and guangxi local lemon (C. limonia). Our data also demonstrated that sweet orange and sour orange were hybrids of mandarin (C. reticulata) and pummelo, while rough lemon was a cross between citron and mandarin. For mexican lime (C. aurantifolia), our molecular data confirmed a species of Papeda to be the female parent and C. medica as the male. These findings provide new information for future study on the taxonomy, evolution, and genetic breeding of Citrus.