No abstract

No abstract

The variability and genetic parameters of seven agronomic characteristics were estimated for 11 genotypes, and high values of the phenotypic coefficient of variation (PCV) of capsaicin content (CC) were obtained. Heritability (h2) was high for yield per plant (YP; 0.98) and CC (0.93). The principal components analysis (PCA) revealed that the first three components explained 94.02% of the total variation; therefore, genotypes with higher YP values and fruit weight (FW) (AKN-08, ASBC-09) were placed in quadrant I. Those with greater CC and lowest YP and FW (MBI-11, RES-05) were placed in quadrant II. The greatest fruit length (RNJ-04) was placed in quadrant III. Those with the greatest number of fruits per plant (NBA-06, RKI-01, RHC-02, RHN-03, NKA-07, and MSB-12) were placed in quadrant IV. The results showed that the genotypes studied comprise an excellent source of genetic material for Habanero pepper improvement programs.

Amaranthus (Amaranthaceae) is a widespread genus that includes noxious weeds, economically important species for food, forage, medicinals and ornamentals. Three species of Amaranthus have been cultivated for their grain in the world, i.e. A. hypochondriacus, A. caudatus, and A. cruentus. It has been postulated that A. cruentus was domesticated from the probable wild progenitor A. hybridus, and that the domestication event occurred between southern Mexico and Guatemala, the region where the Mayan civilization flourished. Morphological variation in this grain amaranth and its putative wild progenitor has been poorly documented, even though this area is a possible center of domestication of A. cruentus. Samples of A. cruentus, A. hybridus, hybrids between these two species and aberrant morphotypes collected were studied morphologically using multivariate statistical methods on pistillate floral characters to (1) assess the diversity of grain amaranth A. cruentus and its postulated wild progenitor A. hybridus in the proposed domestication center of origin, (2) test the hypothesis that some hybrids and aberrant morphotypes found in the region can be morphologically differentiated from A. hybridus and A. cruentus based on statistical analyses, and (3) test and review the diagnostic characters traditionally used for assessing species circumscription. Our results showed high morphological diversity for these two species in the study region, indicating differentiation of both species, apparently based primarily on hybridization. Morphological variants on flower, bract, sepal, seed, and fruit characters were significant for confirming and circumscribing species.

<pre><strong><span lang="EN-US">Background. </span></strong><em><span lang="EN-US">Jatropha curcas</span></em><span lang="EN-US"> L. is a crop whose oil can be converted to biodiesel. However, there is lack of varieties with high yields that limiting commercial production of the crop. An alternative is to obtain <em>in vitro </em>plants from unpollinated female gametophytes is known as gynogenesis which can provide an alternative to </span><span lang="EN-US">produce </span><span lang="EN-US">varieties with increased seed production.<strong> Objective</strong>. The objective was to establish a protocol for obtaining <em>in vitro</em> plants from unfertilized ovules of <em>Jatropha curcas</em> L. ovules. <strong>Methodology</strong>. The ovules were extracted from unfertilized inflorescences pretreated for 0, 1, 3 and 7 days at 2 to 5 ° C. Three combinations of plant growth regulator treatments were applied to culture media for induction of gynogenic calli. Gynogenic calli were cultured on MS basal medium with BAP and IBA for development of green, friable. The </span><span lang="EN-US">gynogenic </span><span lang="EN-US">calli from the development treatment </span><span lang="EN-US">were transferred to experiments to determine a regeneration treatment. </span><span lang="EN-US">The gynogenic plantlets were transferred to different treatments for root development. <strong>Results</strong>. The results show that pretreatment of inflorescences at 2 to 5°C had no significant effect on the number of ovules that formed friable white calli. Induction of gynogenic friable white calli occurred in the dark conditions, on half-strength </span><span lang="EN-US">Murashige and Skoog basal medium (</span><span lang="EN-US">½</span><span lang="EN-US"> MS) </span><span lang="EN-US">supplemented with two combinations of growth regulators: (i) 5.37 µM naphthalene acetic acid (NAA) combined with 6.65 µM 6-benzylaminopurine (BAP) and, (ii)</span><span lang="EN-US">8.05 µM NAA with 22.09 µM BAP. Development of green, friable, gynogenic calli under light–dark conditions was possible under treatment with complete Murashige and Skoog (1962) (MS) basal medium with 6.66 µM BAP and 4.9 µM indole-butyric acid (IBA).</span><span lang="EN-US">Friable green callus formed gynogenic embryos on MS basal medium supplemented with </span><span lang="EN-US">22.09 </span><span lang="EN-US">µM</span><span lang="EN-US">BAP and </span><span lang="EN-US">3.40 </span><span lang="EN-US">µM</span><span lang="EN-US"> paclobutrazol (PBZ), embryos regeneration occurred in photoperiod conditions</span><span lang="EN-US">. </span><span lang="EN-US">Embryos were able to develop and convert to plantlets in the treatment on MS basal medium containing 2.22 µM BAP and 0.28 µM of indole-3-acetic acid (IAA).</span><span lang="EN-US"> Root development of </span><span lang="EN-US">plantlets</span><span lang="EN-US"> occurred in </span><span lang="EN-US">½</span><span lang="EN-US"> MS basal medium with 18.65 µM IBA. <strong>Implications</strong>. A protocol of <em>in vitro</em> gynogenesis in <em>Jatropha curcas</em> would contribute to the improvement of its cultivation, reducing the time required for the generation of pure lines that would allow us to obtain varieties with increased seed production. <strong>Conclusions. </strong>The<strong> </strong></span><span lang="EN-US">work presented here describes a reproducible protocol to produce plants <em>in vitro</em> from unfertilized ovules of <em>Jatropha curcas</em> L. T</span><span lang="EN-US">his methodology will facilitate to obtain homozygotic lines with significant reduction in the time required by conventional methods. </span><strong></strong></pre>