Avocado rootstock named ‘KB1’

Abstract

A new avocado variety, KB1, was discovered in Chincha, Peru. The KB1 variety when used as a rootstock is notable for its prolific and vigorous feeder root growth ability that results in rapid canopy volume and early productivity of the Hass avocado scion cultivar, and induces larger fruit sizes of the Hass cultivar and is an alternative for locations where ecologic conditions tend to produce small fruit.

Claims

1. A new and distinct avocado rootstock, as herein illustrated and described.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying photographs show specimens of the tree and plant parts of the new KB1 variety.

(2) FIG. 1 is a photograph of the KB1 foundation tree growing in Chincha, Peru;

(3) FIG. 2 is a photograph depicting lenticels of the KB1 variety;

(4) FIG. 3 is a photograph depicting flush foliage of the KB1 variety;

(5) FIG. 4 is a photograph depicting inflorescence of the KB1 variety;

(6) FIG. 5 is a photograph depicting an external view of the fruit of the KB1 variety;

(7) FIG. 6 is a photograph depicting an internal view of the fruit of the KB1 variety, with and without the seed;

(8) FIG. 7 is a graph depicting the comparison of tree canopy diameter for the KB1 variety as compared to other avocado varieties;

(9) FIG. 8 is a graph depicting the yield of fruit for the KB1 variety as compared to other varieties; and

(10) FIG. 9 is a graph depicting the percentage of defective fruit of the KB1 variety as compared to other avocado varieties.

DETAILED BOTANICAL DESCRIPTION OF THE VARIETY

(11) The following detailed botanical description is based on observations of a KB1 rootstock variety which was taken from an approximately sixteen-year-old mature tree, planted in 2000 in Chincha, Peru, and evaluations conducted in 2016 for Hass on KB1 clonal rootstock planted between 2010 and 2014 in Chincha, Peru.

(12) In those instances where precise color assessment could be made, references are to The Royal Horticultural Society (R.H.S.) Colour Chart Sixth Edition (2015). In other instances, generally, color terms are used in accordance with an ordinary dictionary significance. Other descriptions are taken from the generally recognized description chart found in the Graphic Handbook for the Description of Avocado Varieties published by SAGARPA in January, 2010 (ISBN: 978-607-12-0106-5) (Graphic Handbook).

(13) With reference to FIG. 1, the KB1 foundation tree is shown which was planted in 2000 in Chincha, Peru. The tree is now approximately eight meters tall and six meters in diameter. An aspect of KB1 is that it has rapid uniform growth. The KB1 has a generally upright tree shape. The color of a one-year-old branch is strong yellow green (RHS 144B). Young shoots have a soft, juicy texture. The color of expanding apical leaves of young shoots is moderate yellowish brown (RHS N199C).

(14) As illustrated in FIG. 2, the lenticels found on the KB1 tree are big, long and horizontal. The color of the lenticels (one-year-old bark) are moderate brown (RHS 200C). The bark texture of a one-year-old branch is smooth. One-year-old bark has a moderate orange yellow color (RHS 165C), while the oldest bark growth has a dark grayish yellow color (RHS 199D).

(15) FIG. 3 illustrates typical flush foliage of KB1. The young shoot color is moderate yellowish brown (RHS N199C). The leaf blade anise aroma is strong, indicating Mexican origin. The Graphic Handbook uses the presence or absence of anise smell in the leaf blade as an indication of the tree origin; West Indian having no smell, whereas Mexican has anise smell.

(16) The leaf arrangement is alternate relative to shoot (Graphic Handbook). Mature leaves have a weak undulation margin. The leaf venation pattern of a mature, fully expanded leaf is camptodromous, pinnate venation, as illustrated. An upper surface vein has a brilliant greenish yellow color (RHS 151D). The veins of a mature, fully-expanded leaf are level (Graphic Handbook). A mature, fully expanded, leaf typically has an intermediate number of secondary veins between 14.5 and 17.5 secondary veins on the leaf blade.

(17) The density of pubescence on the lower surface of a mature leaf is medium. Medium density of pubescence on the lower surface of a mature leaf is shown in the Graphic Handbook under element 17. Texture of upper surface of mature leaves is smooth.

(18) Twisting along the whole length of the leaf blade of a mature leaf is absent. The shape of the apex of the leaf blade is acuminate. The leaf base shape of a mature, fully expanded leaf is equilateral. The leaf blade length is medium (16.1 cm-18.4 cm) (Graphic Handbook). The leaf blade width of a mature, fully expanded leaf is also medium (6.6 cm-7.6 cm) (Graphic Handbook).

(19) The color of the upper surface of a mature fully expanded leaf is greyish olive green (RHS NN 137B). The color of the lower surface of a mature, fully expanded leaf is pale green (RHS N 138C). The color of tender, fully grown leaves is moderate olive green (RHS 146A).

(20) The length of a mature, fully expanded leaf petiole is medium (between 3.9 cm and 4.62 cm) (Graphic Handbook). The diameter of a mature, fully expanded leaf petiole is approximately 2.5 mm. The color of a mature, fully expanded leaf petiole is moderate yellow green (RHS 146C).

(21) With reference now to FIG. 4, typical inflorescence of the KB1 variety is shown. The cutting illustrated measures approximately 4.09 cm-6.53 cm. The KB1 variety has a B flowering type. The flower fragrance of a fully opened flower is absent. The perianth (sepals and petals) of a newly, fully opened flower is borne in two whorls of three perianth lobes. The length of a fully developed flower bud is approximately nine millimeters, and the diameter is approximately five millimeters. There are nine stamen of a fully opened flower. The pistil of the fully opened flower has one each of a stigma, style and ovary. The ovary is superior. The color of a fully developed flower bud is brilliant yellow green (RHS 150C). The petal color of the fully opened flower, on both surfaces, is light yellow green (RHS 154C).

(22) In its native Peru, the spring bloom period extends from early August through mid-October. KB1 rarely has off-season flowers. Fruit set is poor and only a very few fruits ripen.

(23) With reference to FIG. 5, an exterior view of a typical fruit of the KB1 variety is shown. The diameter of the fruit measures 6.60 cm-8.33 cm on average so as to have a relatively small mature fruit diameter, such as an Edranol. The length of the fruit on average measures 10.71 cm-13.23 cm, which is short, as in Edranol. However, the mature fruit ratio length/diameter is medium, as in Topa Topa. The average fruit weight, taken from an average of six mature fruit, is 159 grams.

(24) The color of the fruit skin as it starts to change color is strong yellow green (RHS 143A). Phase 2 in color change of the fruit skin, the color is dark red (RHS 183B). The mature fruit skin color is dark red (RHS 187A). The fruit skin color of a fully ripe fruit is black (RHS 203B).

(25) With continuing reference to FIG. 5, the length of the fully expanded pedicel is short, between 0.99 and 1.45 cm. The shape of the pedicel is conical and does not exhibit a nailhead at the junction. The thickness of the fully expanded pedicel compared to peduncle at junction is thicker, approximately 2 mm. The pedicel surface texture is wrinkled. The fully expanded peduncle is approximately 3.56 cm, with a diameter of approximately 3.2 mm. The color of the fully expanded peduncle is strong greenish-yellow (RHS 151A).

(26) FIG. 6 is a typical internal view of the KB1 variety fruit, illustrating with and without the seed. The shape of the seed in longitudinal section is generally ovate. The seed diameter at the widest equatorial point (taken from an average of four seeds) is 3.175 cm. The average seed length at polar ends, taken from the four seeds, is 4.445 cm. The average weight of the seed is 29.25 grams. The seed color is pale orange yellow (RHS 24D).

(27) With continuing reference to FIG. 6, the color of the flesh of a fully ripe fruit is light yellow-green (RHS 145 B). The lenticel color of the fully ripe fruit is dark red (RHS 187B). As illustrated in FIGS. 5 and 6, the color of the ripe fruit is dark greyish purple (RHS 202A) or black (RHS 203B). The thickness of the skin of the ripe fruit is very thin.

(28) An experimental block of Hass avocado was planted in March 2014 at the inventor's property using four (4) rootstock sources: KB1 clonal, West Indian Waldin seedlings, seedling selection and (hybrid) Mexican x Guatemalan Zutano (unpatented) seedlings. Data taken in 2016 has shown that statistical differences do exist in canopy volume, early productivity, fruit weight (caliper) and cosmetic external quality. All of these measurements show KB1 clonal as the superior rootstock choice under the soil-water-climate conditions of this location. The following is the data of the KB1 avocado rootstock compared to other standard avocado rootstocks, as mentioned above, during the evaluation process in Peru and California.

(29) TABLE-US-00001 TABLE 1 Rootstock Canopy Diameter (Meters) Waldin 5.86 Clonal KB1 7.68 Zutano 5.96 Seedling Selection 5.55

(30) Table 1 above is the average diameter of the tree canopy for Hass on the four different rootstocks, including the KB1 variety. FIG. 7 is a corresponding graph illustrating a comparison of the tree canopy diameter for Hass for the four rootstocks of Table 1.

(31) TABLE-US-00002 TABLE 2 No. of Total Average Rootstock Trees Yield (KG) Yield/Tree (KG) Clonal KB1 92 728.64 7.92 Waldin 80 551.43 6.89 Zutano 84 522.82 6.22 Seedling Selection 73 58.64 0.80

(32) Table 2 is a table illustrating the yield of Hass on the different rootstocks. FIG. 8 is a graph depicting the yield of Hass on the different rootstocks.

(33) TABLE-US-00003 TABLE 3 Defective Defective Rootstock Fruit No. Fruit No. Fruit % Clonal KB1 1483 16 1.08% Zutano 955 87 9.11% Seedling Selection 218 28 12.84% Waldin 1254 171 13.64%

(34) Table 3 illustrates the incidents of defective fruit for the KB1 variety, as compared to the other three different rootstocks, and FIG. 9 is a graph depicting the percentage of defective fruit by rootstock.

(35) As illustrated in Table 4 below, one hundred fruit per rootstock, including the KB1 variety as compared to the other varieties, from two-year-old trees were randomly selected and evaluated in order to classify the fruits by fruit counts (CODEX NORM).

(36) TABLE-US-00004 TABLE 4 Count (g) 8 10 12 14 16 Rootstock (460-575) (365-460) (305-365) (265-305) (235-265) Waldin 2% 12% 23% 19% Clonal KB1 3% 39% 38% Zutano 1% 2% 24% 33% Seedling 1% 2% 13% 44% Selection Count (g) 18 20 22 24 26 Rootstock (210-235) (190-210) (170-190) (155-170) (145-155) Waldin 32% 12% Clonal KB1 16% 4% Zutano 30% Seedling 32% 8% Selection

(37) As shown in Table 5 below, the yield of the Hass cultivar on the four rootstocks, including the KB1 variety, was measured in the two-year-old trees, and the yield extrapolated to one hectare.

(38) TABLE-US-00005 TABLE 5 Yield Total Yield per tree Distance number of per ha Rootstock (kg) (m) trees per ha (ton) Clonal KB1 7.76 6 4 416 3.23 Waldin 6.89 6 4 416 2.87 Zutano 6.2 6 4 416 2.58 Seedling Selection 0.79 4 3 833 0.66

(39) KB1 is to be used commercially as a rootstock. As can be seen from the above, the new and distinct avocado variety KB1 when used as a rootstock confers to the tree a high yield and high vigor when topworked to Hass. Moreover, the KB1 avocado rootstock cultivar variety is notable for its prolific and vigorous feeder root growth ability that results in rapid canopy volume and early productivity of the Hass avocado scion cultivar. The KB1 variety induces larger fruit sizes of the Hass cultivar and is an alternative for locations where ecologic conditions can produce small fruit, such as in well-drained alkaline soils in low rainfall conditions.